• 한국운동역학회지
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• 제26권3호
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• pp.257-264
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• 2016

Objective: The purpose of this study was to determine the periodicity of shank-foot segment coupling and free torque before and after fatigue induced by prolonged running. Method: Fifteen young healthy male participants with a rear-foot strike ran on instrumented dual-belt treadmills at 70% of their maximum oxygen uptake for 65 min. Kinematic and ground reaction force data were collected for 20 continuous strides at 5 and 65 min (considered the fatigued condition). The approximate entropy tool was applied to assess the periodicity of the shank internal-external rotation, foot inversion-eversion, shank-foot segment coupling, and free torque for the two running conditions. Results: The periodicity of all studied parameters, except foot inversion-eversion, decreased after 65 min of running (fatigued condition) for 80% of the participants in this study. Furthermore, 60% of the participants showed similarities in the change of periodicity pattern in shank internal-external rotation, coupling, and free torque. Conclusion: The findings indicated that the foot inversion-eversion motion may pose a higher risk of injury than the shank internal-external rotation, coupling, and free torque in the fatigued condition during prolonged running.

• Biomolecules & Therapeutics
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• 제10권3호
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• pp.152-158
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• 2002

The present study elucidated the effect of $\beta$-carbolines (harmaline and harmalol) on brain mitochondlial dysfunction caused by the tyrosinase-induced oxidation of dopamine. Harmaline, harmalol and antioxidant enzymes (SOD and catalase) attenuated the dopamine-induced alteration of membrane potential, cytochrome c release and thiol oxidation in mitochondria. In contrast, antioxidant enzymes failed to reverse mitochondrial dysfunction induced by dopmnine plus tyrosinase. $\beta$-Carbolines decreased the damaging effect of dopamine plus tyrosinase against mitochondria, except no effect of harmalol on thiol oxidation. Antioxidant enzymes decreased the melanin formation from dopamine in the reaction mixture containing mitochondria but did not reduce the formation of dopamine quinone caused by tyrosinase. Both harmalol and harmaline inhibited the formation of reactive quinone and melanin. Harmalol being more effective for quinone formation and vise versa. The results indicate that compared to MAO-induced dopamine oxidation, the toxic effect of dopamine in the presence of tyrosinase against mitochondria may be accomplished by the dopamine quinone and toxic substances other than reactive oxygen species. $\beta$-Carbolines may decrease the dopamine plus tyrosinase-induced brain mitochondrial dysfunction by inhibition of the formation of reactive quinone and the change in membrane permeability.

• 한국자동차공학회논문집
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• 제20권2호
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• pp.70-77
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• 2012

The selective catalytic reduction(SCR) system used to reduce NOx in diesel engines requires an NO/$NO_2$ ratio of about 1 in exhaust emissions to realize the fast SCR mode at temperatures lower than $300^{\circ}C$. This study investigated the characteristics of a plasma system as a pre-active apparatus for the fast SCR reaction mode of an SCR system. Plasma was generated by the pulse corona discharge(PCD) method with a four-channel wire-cylinder reactor. This study showed that plasma was easily generated in the exhaust gas by the PCD system, and the peak voltage of the normal state condition for plasma generation was generally 12 kV. The PCD system easily converted NO into $NO_2$ at lower temperatures and the NO/$NO_2$ conversion ratio increased with the discharge current for plasma generation. But the PCD system could not convert NO into $NO_2$ at higher engine speeds and higher engine loads due to the lack of oxygen in exhaust gas. The PCD system also activated the diesel oxidation catalysts(DOC) system to reduce CO emissions.

• 한국분말재료학회지
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• 제8권3호
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• pp.201-206
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• 2001

$>LaMnO_3$$(La, Sr)MO_3$, and $(La, Sr)MO_3/YSZ$ gel films were deposited by spin-coating technique on scandium-doped zirconia (YSZ) substrate using the precursor solution prepared from $La(O-i-C_3H_7)_3$, $Co(CH_3COO)_2$or $Mn(O-i-C_3H_7)_2$,2-methoxyethanol, and polyethylene glycol. By heat-treating the gel films, the electrochemical cells, $(La, Sr)MnO_3{\mid}ScSZ{\mid}Pt$ were fabricated. The effect of polyethylene glycol on the microstructure evolution of $$LaCoO_3and $LaMnO_3$thin films was investigated, and NOx decomposition characteristics of the electrochemical cells were investigated at $500^{\circ}C$ to $600^{\circ}C$. By applying a direct current to the $(La, Sr)MnO_3{\mid}ScSZ{\mid}Pt$ electrochemical cell, good NOx conversion rate could be obtained relatively at low current value even if excess oxygen is included in the reaction gas mixture.

• Journal of Pharmaceutical Investigation
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• 제3권3호
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• pp.5-15
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• 1973

The stabilizing effect of promazine hydrochloride injectin was tested by irradiation of sun lamp(5,000 Lux) on their acid solution sealed in ampules under various stabilizers. The result of experimentation on the color change, the remaining proportion and the half life of promazine hydrochloride solution is as follows. 1. Instability of promazine hydrochloride solution is mainly caused by the sunlight and oxygen. 2. The pH range of promazine hydrochloride injection is recommended to $pH\;4.4{\sim}5.2$ 3. The decomposition of promazine hydrochloride by the sunlight is composed of pseudo zero order reaction when It maintains colorless solution. 4. The half life of 0.5% promazine hydrochloride injection was 30 hrs. under sun lamp irradiation, but it was delayed to 84 hrs. by the simple stabilizer and to 175 hrs. by compound stabilizer. 5. The stabilizing effect of promazine .hydrochloride injection adding sod. metabisulfite$(Na_2S_2O_5)$ was most excellent in various simple stabilizers and adding $Na_2S_2O_5$ to nicotinic acid, $Na_2S_2O_5$ to nicotinamide were more excellent than other compound stabilizers.

• International Journal of Automotive Technology
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• 제2권2호
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• pp.77-83
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• 2001

Effect of ethene on the $DeNO_X$ conversion process in a simulated diesel engine operating conditions was investigated experimentally and theoretically. With the addition of even a small amount of ethene the NO to $NO_2$ conversion enhances greatly. The energy required to convert one NO molecule is 27 eV with 250 ppm ethene added, while 137 eV without ethene at 473 K. The effect of energy density, temperature, and the initial concentrations of ethene and oxygen are also discussed and the results show that the increase of the mentioned parameters lead to the promotion of NO oxidation. A kinetic model used in this study shows good agreement with the experimental result. Byproducts like formaldehyde ($CH_2$ 0) and methyl nitrite ($CH_3$ ONO) predicted by model calculation are broken up into CO and $H_2O$ eventually when high energy is delivered to the gas mixture. Sensitivity analysis shows that the main reactions of NO oxidation when ethene is added we: $HO_2+ NO \arrow NO_2 + OH, RO_2 + NO \arrow NO_2 + RO$, where R is a hydrocarbon radical. Also the direct oxidizing reaction of NO with O cannot be neglected.

• 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.

• 한국세라믹학회지
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• 제26권6호
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• pp.811-819
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• 1989

There have been many studies on the biological phenomena of Bioglasses, which nay be used as implant materials in human body. However, not many works on the Bioglass compositions have been reported. In the present study, the effect of Al2O3 substitution for SiO2 in Bioglass of Na2O-CaO-P2O5-SiO2 system on its structure and properties was examined. Infrared and Raman spectroscopic studies for the glass structural analysis, differential thermal analysis and X-ray diffraction analysis for crystallization of the glass were perfomed. Several physical properties, such as thermal expansion coefficient, softening point, microhardness and reaction phenomena, were also measured. The major crystalline phase, after heat treatment of the glasses, was Na2Ca2(SiO2)3 and the crystal was transformed into other phase with increased substitution of Al2O3. The added Al2O3 reduced non-bridging oxygen in glass structure and thermal expansion coefficient, but increased glass density, sofening point and microhardness. When the glasses are reacted in Tris-buffer solution, the substituted Al2O3 inhibited the formation of hydroxyapatite on the Bioglas surface, and no hydroxyapatite was formed for the sample which contained more than 6wt.% of Al2O3 even if they were reacted for 600 hours.

• 한국세라믹학회지
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• 제51권4호
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• pp.307-311
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• 2014

ZnS and $ZnS/TiO_2$ were prepared by chemical deposition. The prepared photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), and transmission electron microscopy (TEM). The generation of reactive oxygen species was detected by monitoring the oxidation reaction from 1,5-diphenyl carbazide (DPCI) to 1,5-diphenyl carbazone (DPCO). Excellent catalytic degradation of methylene blue (MB) solution was observed using the $ZnS/TiO_2$ composites during irradiation with visible light. The results show that the photocatalytic performance of $TiO_2$ nanoparticles is improved by loading with ZnS.

• 한국전기전자재료학회논문지
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• 제19권11호
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• pp.985-993
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• 2006

An experiment to find out the removal mechanism of PEG(polyethyleneglycol) by using UV-enhanced $O_2$ GPC (gas phase cleaning) at low substrate temperature below $200^{\circ}C$ was executed under various process conditions, such as substrate temperature, UV exposure, and $O_2$ gas. The possibility of using $UV/O_2$ GPC as a low-temperature in-situ cleaning tool for organic removal was confirmed by the removal of a PEG film with a thickness of about 200 nm within 150 sec at a substrate temperature of $200^{\circ}C$. Synergistic effects by combining photo-dissociation and photo oxidation can only remove the entire PEG film without residues within experimental splits. In $UV/O_2$ GPC with substrate temperatures higher than the glass transition temperature, the substantial increase in the PEG removal rate can be explained by surface-wave formation. The photo-dissociation of PEG film by UV exposure results in the formation of end aldehyde by dissociation of back-bone chain and direct decomposition of light molecules. The role of oxygen is forming peroxide radicals and/or terminating the dis-proportionation reaction by forming peroxide.