• The Korean Journal of Pharmacology
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• v.24 no.1
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• pp.53-61
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• 1988

The effect of antioxidants on the myocardial cellular damage which occurs during reoxygenation of hypoxic myocardium was examined in isolated rat hearts. The roles of oxygen free radical and lipid peroxidation in reoxygenation injury of myocardium were also investigated. In Langenorff preparation of isolated rat heart, which was made hypoxic by perfusion with the substrate free, hypoxic cardioplegic solution ($37^{\circ}C$, 90 min), the release of cytosolic enzymes (creatine phosphokinase, lactic dehydrogenase) and a lipid peroxidation product, malondialdehyde into the coronary effluent were abruptly increased by reoxygenation. The release of enzymes was closely parallel to that of MDA. These increases of enzymes and lipid peroxidation product were suppressed to various degrees in the presence of scavengers of superoxide anion (superoxide dismutase, 10,000 U), hydrogen peroxide (catalase, 25,000 U) and hydroxyl radical (dimethyl sulfoxide, 10%). A natural antioxidant, ${\alpha}-tocopherol$(4.5 uM) and a synthetic one, butylated hydroxytoluene (2 uM) suppressed the release of cytosolic enzymes with the concomittent reduction of lipid peroxidation as measured by malondialdehyde release into the coronary effluent. These effects of antioxidants were dose dependent, and were more pronounced when the antioxidants were administered throughout hypoxic and reoxygenation periods than given during reoxygenation period only. These results suggest that cytotoxic oxygen free radicals produced in the myocardium during reoxygenation may be responsible fur the myocardial cellular injury by enhancing the lipid peroxidation of cellular membranes. Furthermore, the antioxidants may exert protective effect against reoxygenation damage of hypoxic myocardium through the inhibition of lipid peroxidation reaction.

• Nuclear Medicine and Molecular Imaging
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• v.40 no.4
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• pp.228-232
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• 2006

Purpose: electrophilic $^{18}F(T_{1/2}=110\;min)$ radionuclide in the form of $[^{18}F]F_2$ gas is of great significance for labeling radiopharmaceuticals for positron omission tomography (PET). However, its production In high yield and with high specific radioactivity is still a challenge to overcome several problems on targetry. The aim of the present study was to develop a method suitable for the routine production of $[^{18}F]F_2$ for the electrophilic substitution reaction. Materials and Methods: The target was designed water-cooled aluminum target chamber system with a conical bore shape. Production of the elemental fluorine was carried out via the $^{18}O(p,n)^{18}F$ reaction using a two-step irradiation protocol. In the first irradiation, the target filled with highly enriched $^{18}O_2$ was irradiated with protons for $^{18}F$ production, which were adsorbed on the inner surface of target body. In the second irradiation, the mixed gas ($1%[^{19}F]F_2/Ar$) was leaded into the target chamber, fellowing a short irradiation of proton for isotopic exchange between the carrier-fluorine and the radiofluorine absorbed in the target chamber. Optimization of production was performed as the function of irradiation time, the beam current and $^{18}O_2$ loading pressure. Results: Production runs was performed under the following optimum conditions: The 1st irradiation for the nuclear reaction (15.0 bar of 97% enriched $^{18}O_2$, 13.2 MeV protons, 30 ${\mu}A$, 60-90 min irradiation), the recovery of enriched oxygen via cryogenic pumping; The 2nd irradiation for the recovery of absorbed radiofluorine (12.0 bar of 1% $[^{19}F]fluorine/argon$ gas, 13.2 MeV protons, 30 ${\mu}A$, 20-30 min irradiation) the recovery of $[^{18}F]fluorine$ for synthesis. The yield of $[^{18}F]fluorine$ at EOB (end of bombardment) was achieved around $34{\pm}6.0$ GBq (n>10). Conclusion: The production of $^{18}F$ electrophilic agent via $^{18}O(p,n)^{18}F$ reaction was much under investigation. Especially, an aluminum gas target was very advantageous for routine production of $[^{18}F]fluorine$. These results suggest the possibility to use $[^{18}F]F_2$ gas as a electrophilic substitution agent.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.11a
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• pp.24.1-24.1
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• 2009

Tantalum carbo-nitride($T_aC_xN_y$) films were deposited with chemical vapor deposition(CVD) using tert-butylimido tris-diethylamido tantalum (TBTDET, $^tBu-N=Ta-(NEt_2)_3$, $Et=C_2H_5$, $^tBu=C(CH_3)_3$) between $350^{\circ}C$ and $600^{\circ}C$ with argon as a carrier gas. Fourier transform infrared (FT-IR)spectroscopy was used to study the thermal decomposition behavior of TBTDET in the gas phase. When the temperature was increased, C-H and C-N bonding of TBTDET disappeared and the peaks of ethylene appeared above $450^{\circ}C$ in the gas phase. The growth rate and film density of $T_aC_xN_y$ film were in the range of 0.1nm/min to 1.30nm/min and of $8.92g/cm^3$ to $10.6g/cm^3$ depending on the deposition temperature. $T_aC_xN_y$ films deposited below $400^{\circ}C$ were amorphous and became polycrystal line above $500^{\circ}C$. It was confirmed that the $T_aC_xN_y$ film was a mixture of TaC, graphite, $Ta_3N_5$, TaN, and $Ta_2O_5$ phases and the oxide phase was formed from the post deposition oxygen uptake. With the increase of the deposition temperature, the TaN phase was increased over TaC and $Ta_3N_5$ and crystallinity, work function, conductivity and density of the film were increased. Also the oxygen uptake was decreased due to the increase of the film density. With the increase of the TaC phase in $T_aC_xN_y$ film, the work function was decreased to 4.25eV and with the increase of the TaN phase in $T_aC_xN_y$ film,it was increased to 4.48eV.

• Journal of the Korean Vacuum Society
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• v.10 no.2
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• pp.234-240
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• 2001

The diffusion barrier properties of TiN by using Cu(Mg) alloy film have been investigated. Cu(Mg) alloy film was deposited on air-exposed TiN film. Upon annealing, interfacial MgO of 100 $\AA$ has been formed due to the reaction of Mg with oxygen existed on the surface of TiN. Combined MgO/TiN structure prevented the interdiffusion of Cu and Si up to $800^{\circ}C$. To improve the adhesion of Cu(Mg) alloy film to the TiN, TiN layer was treated by $O_2$ plasma, followed by vacuum annealing at $300^{\circ}C$. It was found that increased oxygen on the surface of TiN film by plasma treatment enhanced segregation of Mg toward the interface, resulting in the formation of dense MgO layer. Improved adhesion characteristics have been formed through this treatment. However, increased power of $O_2$ plasma led to the formation of TiO$_2$ and decreased the Mg content to be segregated to the interface, resulting in the decrease in adhesion property. In addition, the deposition of 50 ${\AA}$ Si on the TiN enhanced the adhesion of Cu(Mg) alloy to TiN without deteriorating the TiN diffusion barrier characteristics.

• Korean Journal of Materials Research
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• v.4 no.6
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• pp.669-680
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• 1994

Oxidation behaviour of TiAl intermetallic compounds with the addition of Cr, V, Si, Mo, or Nb was investigated at 900~$1100^{\circ}C$ under the atmospheric environment. The reaction products were examined by XRD, SEM equipped with WDX. The weight gain by continuous oxidation increased with the addition of Cr or V, but there was less weight gain when Mo, Si or Nb was added individually. he oxidation rate of Cr- or V-added TiAl was always larger than that of TiAI. However, oxidation rate of Si-, Mo- or Nb-added TiAl was almost same or smaller than that of TiAI. Thus, it is concluded that the addition of Cr or V did not improve the oxidation resistance, whereas the addition of Si, Mo or Nb improved the oxidation resistance. Oxides formed on TiAl with Mo, Si, and Nb were found to be more protective, resulting from the decrease in diffusion rate of the alloying elements and oxygen. Nb strengthened the tendency to form $AI_{2}O_{3}$ in the early stage of oxidation, due to the continuous $AI_{2}O_{3}$ layer formation and dense $Tio_{2}+AI_{2}O_{3}$ layer. According to the Pt-marker test of TiAI- 5wt%Nb, oxygen diffused mainly inward while oxides were formed on the substrate surface. Upon thermal cyclic oxidation at $900^{\circ}C$, it is shown that the addition of Cr or Nb improved the adherence of oxide scale to the substrate.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.235-235
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• 2003

The development of a buffer layer is an important issue for the second -generation wire, YBCO coated metal wire. The buffer layer demands not only on the prohibition of the reaction between YBCO and metal substrate, but also the proper lattice match and conductivity for high critical current density (Jc) of YBCO superconductor, In order to satisfy these demands, we suggested CaRuO3 as a useful candidate having that the lattice mismatches with Ni (200) and with YBCO are 8.2% and 8.0%, respectively. The CaRuO3 thin films were deposited on Ni substrates using various methods, such as e-beam evaporation and DC and RF magnetron sputtering. These films were investigated using SEM, XRD, pole-figure and AES. In e-beam evaporation, the deposition temperature of CaRuO3 was the most important since both hi-axial texturing and NiO formation between Ni and CaRuO3 depended on it. Also, the oxygen flow rate had i[n effect on the growth of CaRuO3 on Ni substrates. The optimal conditions of crystal growth and film uniformity were 400$^{\circ}C$, 50 ㎃ and 7 ㎸ when oxygen flow rate was 70∼100sccm In RF magnetron sputtering, CaRuO3 was deposited on Ni substrates with various conditions and annealing temperatures. As a result, the conductivity of CaRuO3 thin films was dependent on CaRuO3 layer thickness and fabrication temperature. We suggested the multi-step deposition, such as two-step deposition with different temperature, to prohibit the NiO formation and to control the hi-axial texture.

• Journal of Environmental Science International
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• v.19 no.8
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• pp.951-960
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• 2010

Sediment works as a resource for electric cells. This paper was designed in order to verify how sediment cells work with anodic material such as metal and carbon fiber. As known quite well, sediment under sea, rivers or streams provides a furbished environment for generating electrons via some electron transfer mechanism within specific microbial population or corrosive oxidation on the metal surfaces in the presence of oxygen or water molecules. We experimented with one type of sediment cell using different anodic material so as to attain prolonged, maximum electric power. Iron, Zinc, aluminum, copper, zinc/copper, and graphite felt were tested for anodes. Also, combined type of anodes-metal embedded in the graphite fiber matrix-was experimented for better performances. The results show that the combined type of anodes exhibited sustainable electricity production for ca. 600 h with max. $0.57\;W/m^2$ Al/Graphite. Meanwhile, graphite-only electrodes produced max. $0.11\;W/m^2$ along with quite stationary electric output, and for a zinc electrode, in which the electricity generated was not stable with time, therefore resulting in relatively sharp drop in that after 100 h or so, the maximum power density was $0.64\;W/m^2$. It was observed that the corrosive reaction rates in the metal electrodes might be varied, so that strength and stability in the electric performances(voltage and current density) could be affected by them. In addition to that, COD(chemical oxygen demand) of the sediment of the cell system was reduced by 17.5~36.7% in 600 h, which implied that the organic matter in the sediment would be partially converted into non-COD substances, that is, would suggest a way for decontamination of the aged, anaerobic sediment as well. The pH reduction for all electrodes could be a sign of organic acid production due to complicated chemical changes in the sediment.

• Resources Recycling
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• v.24 no.1
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• pp.35-42
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• 2015

To obtain the fundamental information on the dissolution of nickel into the slag in the pyrometallurgical processes for treatment of wasted PCB, the distribution ratios of nickel between CaO-$SiO_2-Al_2O_3$-MgO slag and copper-5 wt%Ni alloy were measured at 1623 K to 1823 K under a controlled $CO_2$-CO atmosphere. The distribution ratio of Ni increased linearly with increasing oxygen partial pressure. Therefore, the dissolution reaction of nickel into the slags could be described by the following equation; $$Ni(l)_{metal}+\frac{1}{2}O_2(g)NiO(l)_{slag}$$ The distribution ratio of Ni increased linearly with increasing content of basic oxides(CaO and MgO) in slag. However, the distribution ratio of Ni decreased linearly with increasing temperature. From these results, the empirical equation of distribution ratio of Ni was obtained by the following equation from the analysis of experimental conditions by multiple regression. $${\log}L_{Ni}=0.4000{\log}P_{O2}-5.1{\times}10^{-4}T+0.3375\(\frac{X_{CaO}+X_{MgO}}{X_{SiO2}}\)$$

• Korean Journal of Environmental Agriculture
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• v.35 no.2
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• pp.121-127
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• 2016

BACKGROUND: Anaerobic digestion is the most feasible technology because not only the energy embedded in organic matters can be recovered, but also they are stabilized while being degraded. This study carried out to improve methane yield of slaughterhouse wastewater treatment sludge cake by the thermal pre-treatment prior to anaerobic digestion.METHODS AND RESULTS: Slaughterhouse wastewater treatment sludge cake was pre-treated by the closed hydrothermal reactor at reaction temperature of 190℃. BMPs (Biochemical methane potential) of the thermal hydrolysate was tested in the different S(Substrate)/I(Inoculum) ratio conditions. COD(Chemical oxygen demand) and SCOD(Soluble chemical oxygen demand) contents of thermal hydrolysate were 10.99% and 10.55%, respectively, then, the 96.00% of COD was remained as a soluble form. The theoretical methane potential of thermal hydrolysate was 0.51 Nm³ kg^-1-VS_added. And BMPs were decreased from 0.56 to 0.22 Nm³ kg^-1-VS_added when S/I ratio were increased from 0.1 to 2.0 in the VS content basis. Those were decreased from 0.32 to 0.13 Nm³ kg^-1-COD_added when S/I ratio were increased from 0.1 to 2.0 based on COD content. The anaerobic degradability of VS basis have showed 196.9%, 102.2%, 80.7%, 67.4%, and 39.4% in S/I ratios of 0.1, 0.3, 0.5, 1.0, and 2.0, respectively. Also the COD of 119.6%, 76.3%, 70.1%, 69.0%, and 43.1% were degraded anaerobically in S/I ratios of 0.1, 0.3, 0.5, 1.0, and 2.0, respectively.CONCLUSION: BMPs obtained in the S/I ratios of 0.1 and 0.3 was overestimated by the residual organic matters remaining at the inoculum. And inhibitory effect was observed in the highest S/I ratio of 2.0. The optimum S/I ratios giving reasonable BMPs might be in the range of 0.5 and 1.0 in S/I ratio. Therefore VS biodegradability of thermal hydrolysate was in 67.4-80.7% and COD biodegradability showed 69.0-70.1%.

• Journal of the Korean Society for Marine Environment & Energy
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• v.3 no.4
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• pp.56-64
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• 2000

Behavior of trace metals in Masan Bay, Korea was studied in August 1998 when the oxygen deficient condition occurred. Dissolved Cd and Zn concentration in the surface waters decreased with increasing distance from Masan Harbor. Dissolved concentrations of Cd, Cu Pb and Zn in the surface waters were higher than bottom waters. Particulate(acid-teachable fraction) concentrations of Cu, Cd and Pb in the surface waters of Masan Bay decreased with increasing distance from Masan Harbor. Bottom waters contained higher concentrations of particulate Cd, Cu, Pb and Zn than surface waters. Distribution coefficients between dissolved and particulate phase (K/sub d/) of Cu and Cd decreased with the increasing distance from the Harbor, possibly due to reaction of these elements with sewage-derived particulate matter Al, Zn, Cu, Cd, and Pb in the surface sediment showed relatively high concentration in the inner Masan Bay.