• Transactions of the Korean hydrogen and new energy society
• /
• v.17 no.4
• /
• pp.440-447
• /
• 2006

Solid polymer electrolyte(SPE) membrane with electrodes embedded on both faces offer unique possibilities for the electrochemical cells like water electrolyzer with fuel cell. The Nafion 117 membrane was used as the SPE, and $Pt(NH_3)_4Cl_2$ and $NaBH_4$ as the electrocatalysts and reducing agent, respectively. The 'impregnation-reduction(I-R) method' has been investigated as a tool for the preparation of electrocatalysts for water electrolyzer by varying the concentration of reducing agent and reduction time at fixed concentration of platinum salt, 5 mmol/L. Pt-SPE electrocatalysts prepared by non-equilibrium I-R method showed the lowest cell voltage of 2.17 V at reduction time, 90 min and with concentration of reducing agent 0.8 mol/L and the cell voltage with those by equilibrium I-R method was 2.42 V at reduction time, 60 min and with concentration of reducing agent 0.8 mol/L. The cell voltage were obtained at a current density $1\;A/cm^2$ and $80^{\circ}C$. In water electrolysis, hydrogen production efficiency by Pt-SPE electrocatalyst is 68.2% in case of non-equilibrium I-R method and 61.2% at equilibrium I-R method.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.25 no.5
• /
• pp.934-944
• /
• 2011

This study was designed to investigate the effects of Kyungohkgo to improve aerobic capacity and eliminate exercise-induced fatigue in high school soccer players. Twenty four subjects were participated and randomly assigned into two groups [KG, Kyungohkgo group (n=12); PG, Placebo control group (n=12)]. Two groups were completed treadmill exercise protocol using graded exercise test at before and after experimental treatment of 4 weeks. The $VO_2$max and endurance time were measured by gas analysis and heart rate (HR) was measured by polar system at pre, post 0, post 5, post 15, post 30 and post 60 minutes. Blood samples were collected to analyze blood components. 1. The $VO_2$max was significant increased in the group of after intake Kyungohkgo compared to the group of after intake placebo (p<.05). 2. The HR was significant decreased in the group of after intake Kyungohkgo compared to the group of after intake placebo during recovery time at post 5 mins(p<.05), 30 mins(p<.01), 60 mins(p<.01). 3. Weight, body mass index, percent body fat, anaerobic threshold, endurance time, blood lactate concentrate, lactate dyhydrogenase, creatine kinase, serum glutamic oxaloacetic transaminase, serum glutamic pyruvic transaminase, other energy sources(total-cholesterol, triglyceride, high density lipoprotein-cholesterol, low density lipoprotein-cholesterol, creatinine) and electrolyte (Na, K, Cl) were shown no significant differences between groups. These results suggested that Kyungohkgo can be used as ergogenic aids to improve aerobic capacity and eliminate exercise-induced fatigue.

• Biomolecules & Therapeutics
• /
• v.11 no.1
• /
• pp.41-50
• /
• 2003

General pharmacological properties of DA-8159, a new pyrazolopyrimidinone derivative were examined in laboratory animals to investigate its safety profile. The oral administration of DA-8159 (1, 5 or 30 mg/kg) in mice and rats had no effect on general behaviors and central nervous system of the animals in test systems, such as hexobarbital-induced sleeping time, motor coordination, normal body temperature, writhing syndromes induced by 0.75% acetic acid solution, chemo-shock produced by pentetrazole solution and rotar rod test. Anesthetized cats treated intravenously with DA-8159 (0.1, 0.3, 1, 3 or 10 mg/kg) showed transient and mild decrease in blood pressure. However, heart rate, respiration rate and tidal volume were not changed by intravenous DA-8159. In the isolated organs including ileum, heart (sinus rate of atria and contractility of papillary muscle), trachea of guinea pigs and phrenic nerve of rats, DA-8159 ($10^{-8}$ ∼$10^{-5}$ mg/L) did not elicit any effect or inhibitory action on the chemically or electrically stimulated contraction. DA-8159 did not influence gastric secretion, pH and total acid output in rats and intestinal propulsion in mice. The administration of DA-8159 in rats had no effect on the platelet aggregation induced by ADP in rabbit plasma, urinary volume and electrolyte ion ($Na^{+}$, $K^{+}$, $Cl^{-}$) excretion in rats. Prothrombin time (PT) of the rats showed a mild but significant increase after administration of DA-8159. Activated partial thromboplastin time (APTT), however, was not affected by DA-8159. These results indicate that DA-8159 does not exert any of serious pharmacological effects.

• Carbon letters
• /
• v.25
• /
• pp.14-24
• /
• 2018

Electrochemical properties and performance of composites performed by incorporating metal oxide or metal hydroxide on carbon materials based on graphene and carbon nanotube (CNT) were analyzed. From the surface analysis by field emission scanning electron microscopy and field emission transmission electron microscopy, it was confirmed that graphene, CNT and metal materials are well dispersed in the ternary composites. In addition, structural and elemental analyses of the composite were conducted. The electrochemical characteristics of the ternary composites were analyzed by cyclic voltammetry, galvanostatic charge-discharge tests, and electrochemical impedance spectroscopy in 6 M KOH, or $1M\;Na_2SO_4$ electrolyte solution. The highest specific capacitance was $1622F\;g^{-1}$ obtained for NiCo-containing graphene with NiCo ratio of 2 to 1 (GNiCo 2:1) and the GNS/single-walled carbon $nanotubes/Ni(OH)_2$ (20 wt%) composite had the maximum specific capacitance of $1149F\;g^{-1}$. The specific capacitance and rate-capability of the $CNT/MnO_2/reduced$ graphene oxide (RGO) composites were improved as compared to the $MnO_2/RGO$ composites without CNTs. The $MnO_2/RGO$ composite containing 20 wt% CNT with reference to RGO exhibited the best specific capacitance of $208.9F\;g^{-1}$ at a current density of $0.5A\;g^{-1}$ and 77.2% capacitance retention at a current density of $10A\;g^{-1}$.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2017.05a
• /
• pp.159-159
• /
• 2017

Ti-6Al-4V alloy have been used for dental implant because of its excellent biocompatibility, corrosion resistance, and mechanical properties. However, the integration of such implant in bone was not in good condition to achieve improved osseointergraiton. For solving this problem, calcium phosphate (CaP) has been applied as coating materials on Ti alloy implants for hard tissue applications because its chemical similarity to the inorganic component of human bone, capability of conducting bone formation and strong affinity to the surrounding bone tissue. Various metallic elements are known to play an important role in the bone formation and also affect bone mineral characteristics. Especially, Zn is essential for the growth of the human and Zn coating has a major impact on the improvement of corrosion resistance. Plasma electrolytic oxidation (PEO) is a promising technology to produce porous and firmly adherent inorganic Zn containing TiO2(Zn-TiO2)coatings on Ti surface, and the a mount of Zn introduced in to the coatings can be optimized by altering the electrolyte composition. In this study, effect of Zn content on the corrosion behavior of Ti-6Al-4V alloy after plasma electrolytic oxidation were studied by SEM, EDS, XRD, AC impedance, and potentiodynamic polarization test. The potentiodynamic polarization and AC impedance tests for corrosion behaviors were carried out in 0.9% NaCl solution at similar body temperature using a potentiostat with a scan rate of 1.67 mV/s and potential range from -1500 mV to +2000 mV. Also, AC impedance was performed at frequencies ranging from 10 MHz to 100 kHz for corrosion resistance.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.22 no.5
• /
• pp.1223-1235
• /
• 2008

This experiment was performed to investigate the effects of Hyeonsamdansameum(HDE) on hypertension. For the study of HDE, we had divided Sprague-Dawley rats to three groups-normal, control, HDE. The control group was injected subcutaneous with monocrotaline(50 mg/kg). The treatment group was injected subcutaneous with monocrotaline(50 mg/kg) and orally administered with HDE extract for 4 weeks(once a day, 208 mg/kg). Then we measured blood pressure, heart rate, on the plasma aldosterone, catecholamine, electrolyte, uric acid, BUN, creatinine, and observed the lung, cardiac muscle. liver. etc. The results of these were as follows: 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity and superoxide dismutase(SOD) - like activity were increased. reactive oxygen species (ROS) was decreased. Angiotensin converting enzyme(ACE) inhibitory activity was increased in a concentration-dependent by HDE. HDE significantly increased body weight in monocrotaline hypertensive rat, so supported nearly normal group. HDE significantly decreased blood pressure and heart rate in monocrotaline hypertensive rat. HOE significantly decreased aldosterone in adrenocortical hormones. HDE significantly decreased dopamine. norepinephrine, epinephrine. Na+. Cl- were intended to decrease. K+ was decreased significantly by HDE. Uric acid. BUN were significantly decreased and creatinine was intended to decrease by HDE. HDE inhibited lung, liver and heart injury connected with hypertension. These results suggest that HDE is usefully applied in treatment and prevention of hypertension.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.22 no.1
• /
• pp.162-170
• /
• 2008

Kamisungihwalhyul-tang(KSHT) has been used for many years as a therapeutic agent for cerebrovascular disease and hypertension in Oriental Medicine. But the effect of KSHT on hypertension and reactive oxygen is not well-known. This study was examined to investigate the effect of KSHT on hypertension and reactive oxygen. After administering KSHT extract to Sprague- Dawley Rat forinjected subcutaneous with deoxycorticosterone acetate(DOCA) 8 weeks, changes in blood pressure, pulse rate, 2,2-diphenyl-1-picrylhydrazyl, reactive oxygen species, angiotensin converting enzyme, aldosterone, catecholamine levels, electrolyte, uric acid, BUN, creatinine in plasma were examined, and immunohistochemical changes and scanning electron microscopic changes were observed. 2,2-diphenyl-1-picrylhydrazyl(DPPH) scavenging activity was increased, reactive oxygen species(ROS) was decreased in a KSHT concentration-dependent. Angiotensin converting enzyme(ACE) inhibitory activity was increased in a concentration-dependent by KSHT. KSHT significantly decreased the blood pressure and heart rate in DOCA-salt hypertensive rat. KSHT significantly decreased the levels of aldosterone in DOCA-salt hypertensive rat. KSHT significantly decreased the level of dopamine, norepinephrine, epinephrine in DOCA-salt hypertensive rat. $Na^+$, $K^+$ and Cl- were decreased significantly, $Ca^{2+}$ was increased significantly by KSHT. KSHT significantly decreased uric acid, BUN, creatinine.

• Advances in Energy Research
• /
• v.5 no.3
• /
• pp.219-226
• /
• 2017

Electrochemical double layer capacitors (EDLCs) have received a tremendous interest due to their suitability for diverse applications. They have been fabricated using different carbon based electrodes including activated carbons, single walled/multi walled carbon nano tubes. But, graphite which is one of the natural resources in Sri Lanka has not been given a considerable attention towards using for EDLCs though it is a famous carbon material. On the other hand, EDLCs are well reported with various liquid electrolytes which are associated with numerous drawbacks. Gel polymer electrolytes (GPE) are well known alternative for liquid electrolytes. In this paper, it is reported about an EDLC fabricated with a nano composite polyethylene oxide based GPE and two Sri Lankan graphite based electrodes. The composition of the GPE was [{(10PEO: $NaClO_4$) molar ratio}: 75wt.% PC] : 5 wt.% $TiO_2$. GPE was prepared using the solvent casting method. Two graphite electrodes were prepared by mixing 85% graphite and 15% polyvinylidenefluoride (PVdF) in acetone and casting n fluorine doped tin oxide glass plates. GPE film was sandwiched in between the two graphite electrodes. A non faradaic charge discharge mechanism was observed from the Cyclic Voltammetry study. GPE was stable in the potential windows from (-0.8 V-0.8 V) to (-1.5 V-1.5 V). By increasing the width of the potential window, single electrode specific capacity increased. Impedance plots confirmed the capacitive behavior at low frequency region. Galvanostatic charge discharge test yielded an average discharge capacity of $0.60Fg^{-1}$.

• Environmental Engineering Research
• /
• v.10 no.3
• /
• pp.138-143
• /
• 2005

Laboratory batch experiments were conducted to evaluate the Fenton degradation rates of phenanthrene. Fenton reactions for the degradation of phenanthrene were carried out with aqueous and slurry phase, to investigate the effects of sorption of phenanthrene onto solid phase. Various types of surfactants and electrolyte solutions were used to evaluate the effects on the phenanthrene degradation rates by Fenton's reaction. A maximum 90% removal of phenanthrene was achieved in aqueous phase with 0.9% of $H_2O_2$ and 300 mg/L of $Fe^{2+}$ at pH 3. In aqueous phase reaction, inhibitory effects of synthetic surfactants on the removal of phenanthrene were observed, implying that surfactant molecules acted as strong scavenger of hydroxyl radicals. However, use of $carboxymethyl-{\beta}-cyclodextrin$ (CMCD), natural surfactant, showed a slight enhancement in the degradation of phenanthrene. It was considered that reactive radicals formed at ternary complex were located in close proximity to phenanthrene partitioned into CMCD cavities. It was also show that Fenton degradation of phenanthrene were greatly enhanced by addition of NaCl, indicating that potent radical ion ($OCI^-$) played an important role in the phenanthrene degradation, although chloride ion might be acted as scavenger of radicals at low concentrations. Phenanthrene in slurry phase was resistant to Fenton degradation. It might be due to the fact that free radicals were mostly reacting with dissolved species rather than with sorbed phenanthrene. Even though synthetic surfactants were added to increase the phenanthrene concentration in dissolved phase, low degradation efficiency was obtained because of the scavenging of radicals by surfactants molecules. However, use of CMCD in slurry phase, showed a slight enhancement in the phenanthrene degradation. As an alternative, use of Fenton reaction with CMCD could be considered to increase the degradation rates of phenanthrene desorbed from solid phase.

• Journal of Korean Society on Water Environment
• /
• v.21 no.3
• /
• pp.242-247
• /
• 2005

In this study, we investigated the removal efficiencies of pollutants and permeate fluxes depending on chemistry of feed water, various molecular weight cut-offs (MWCOs) and materials of membrane, operating pressure. We used seven MWCO membranes of YC0.5, YM1, YM3, YM10, YM30, YM100 and PM30, humic acid solution and surface water as feed water, and examined variation in permeate flux. Results of TOC removal experiment demonstrate that MWCO lower 1,000daltons could remove humic acid effectively. As increasing solution pH and decreasing divalent cations ($Ca^{2+}$) concentration, TOC removal increased. But $UV_{254}$ removal efficiency increased with higher divalent cation concentration and solution pH. Membrane fouling increased with increasing electrolyte (NaCl), divalent cation concentration and decreasing solution pH. In spite of initial permeate flux of the hydrophobic membrane (PM30) was higher than that of the hydrophilic membrane (YM30), flux decline of PM30 was significant during operation. At higher operating pressure, compactness of the cake layer on the membrane surface increased, resulting in gradual increase in hydraulic resistance.