• Bulletin of the Korean Chemical Society
• /
• v.35 no.2
• /
• pp.401-406
• /
• 2014

Metal-containing carbon nanocomposites have shown significance promise in the area of energy storage, heterogeneous catalysis and material science because of their morphology and combined properties. Phosphorus-doped carbon nanocomposites with gold nanoparticles were developed by applying a simple impregnation method and metal deposition technique. Gold-phosphorus supported carbon nanocomposites with two sized (25 and 170 nm) were prepared from economical petroleum pitch residue as the carbon source using an advanced silica template method. These nanocomposites will lead to the novel applications in the field of material science with the combined properties of gold, phosphorus and carbon. The newly prepared gold phosphorus supported carbon nanocomposites were fully characterized using a range of different physico-chemical techniques.

• Proceedings of the Korean Magnestics Society Conference
• /
• 2011.12a
• /
• pp.39-40
• /
• 2011

In this study, the magnetism and the elastic properties of Fe-Si alloys have been investigated using the all-electron FLAPW method based on the GGA. The local magnetic moment of Fe atoms decreases gradually. From the Pugh's relation and $C_P$, in the ordered $D0_3$ $Fe_3Si$, we predict that it presents intrinsic ductility.

• Journal of Electrochemical Science and Technology
• /
• v.15 no.1
• /
• pp.111-131
• /
• 2024

Lignin-derived porous carbon has been identified as a versatile electrode material for supercapacitors (SCs) in energy storage systems (ESSs) owing to their intrinsic advantages including good electrical conductivity, low cost, high thermal and chemical stability, and high porosity, which stem from high surface, appropriate pore distribution, tailored morphologies, heterostructures, and diverse derivates. In this review, to provide a fundamental understanding of the properties of lignin, we first summarize the origin, historical development, and basic physicochemical properties. Next, we describe essential strategies for the preparation of lignin-derived porous carbon electrode materials and then highlight the latest advances in the utilization of lignin-derived porous carbon materials as advanced electrode materials. Finally, we provide some of our own insights into the major challenges and prospective research directions of lignin-derived porous carbon materials for supercapacitors. We believe that this review will provide general guidance for the design of next-generation electrode materials for supercapacitors.

• Elastomers and Composites
• /
• v.45 no.4
• /
• pp.309-315
• /
• 2010

The CIIR blends, which is use for shoes outsole, with SSBR, XNBR and KBR were prepared with various mixing ratio. The viscoelastic properties of these blends, such as tensile modulus, rebound resilience, storage modulus, tan${\delta}$, and creep properties were measured. In the rebound resilience measurement, KBR showed the highest value, which means the lowest energy absorption to stress. As SSBR, XNBR and KBR blends with CIIR, the rebound resilience of the mixtures showed tendency to increase in arithmetic average. In the creep measurement, CIIR showed the highest visconse strain to stress, SSBR and KBR showed lower visconse strain. Maximum tan${\delta}$ peak of CIIR, SSBR and XNBR appeared at $-30^{\circ}C$, $5^{\circ}C$ and $0^{\circ}C$ respectively.

• Journal of the Korean Geotechnical Society
• /
• v.40 no.4
• /
• pp.169-178
• /
• 2024

While stable mid- to large-scale underground hydrogen storage infrastructures are needed to meet the rapidly increasing demand for hydrogen energy, evaluating the safety of explosion vibrations in adjacent buildings is becoming important because of gas explosions in underground hydrogen storage facilities. In this study, a numerical analysis of vibration safety effects on nearby building structures was performed assuming a hydrogen gas explosion disaster scenario in a low-depth underground hydrogen storage facility. A parametric study using a meta-model was conducted to predict changes in ground dynamic behavior for each combination of ground properties and to analyze sensitivity to geotechnical influencing factors. Directly above the hydrogen storage facility, the unit weight of the ground had the greatest influence on the change in ground vibration due to the explosion, whereas, farther away from the facility, the sensitivity of dynamic properties was found to be high. In addition, in evaluating the vibration stability of ground building structures based on the predicted ground vibration data and blasting vibration tolerance criteria, in the case of large reinforced concrete building structures, the ground vibration safety was guaranteed with a separation distance of about 10-30 m.

• Korean Journal of Environmental Biology
• /
• v.28 no.4
• /
• pp.218-222
• /
• 2010

This study was carried out to investigate the changes in the storage characteristics of the Korean traditional raw rice wine (RRW) treated with Korean sun-dried salts and gamma rays. Nowadays, RRWs have received attention because they are a nutritious food with health-stimulating properties. But the rapid deterioration of the fermented RRW is one of the serious problems for brewing and marketing in the world. Actually, the expiry date of the RRW is around a week and this has been a biggest disadvantage of the RRW. The goal of this study was to make it of high quality and extend the period of circulation of the RRW. A lactic acid bacterium was isolated from the RRW. The 16S rRNA sequences of isolates showed 98% homology with the Lactobacillus fermentum. These results suggested that could be manageable improve the shelf life with addition of the sun-dried salts and irradiation with gamma rays.

• Solar Energy
• /
• v.17 no.2
• /
• pp.67-74
• /
• 1997

Spherical shape of phase change material(PCM) has been prepared by using sodium acetate trihydrate as a latent heat storage medium. Gelatin was used as an effective thickener to prevent undesirable phase separation. Sodium pyrophosphate decahydrate was used as nucleator to decrease the degree of supercooling in the thickened phase change material. Spherical PCM particles of 3-3.5 mm in diameter continuously manufactured with molten PCM with those conditions. The particle size of PCM was not affected by the effluent velocity of molten PCM in range of 1.3-1.8 ml/min. DSC, SEM and XRD were also used to characterize the properties of PCM particles.

• New & Renewable Energy
• /
• v.4 no.4
• /
• pp.37-43
• /
• 2008

Three properties of food waste are water 80%, ash 3%, volatile matter 17%. When food waste goes through treatment process such as removal of foreign substances, removal of water as well as sodium, dryness, and pulverization, it transforms into 4,000 Kcal/kg purverized fuel if moisture content is below 13%. Fuel ratio (fixed carbon/volatile matter) of purverized fuel is low compared with bituminuous coal. Ignition temperature measured by thermogravimetry analyzer is about $460^{\circ}C$. Combustion test of purverized fuel have been performed using energy recovery facility which include storage tank of dewatered cake, dryer, hammer mill, combuster including burner, boiler, flue gas treatment equipment. When 160-180 kg/hr of fuel is steadily supplied to burner for 3 hours, combustor temperature reaches about $1000^{\circ}C$ and CO is 77-103 ppm at 1.55 excess air ratio and SOx and Cl are under 2 ppm and 1ppm, respectively. This experiment demonstrate that purverized fuel made from food waste could be an alternative clean energy at the age of high oil price.

• Korean Journal of Materials Research
• /
• v.29 no.2
• /
• pp.121-128
• /
• 2019

Supercapacitors are attracting much attention in sensor, military and space applications due to their excellent thermal stability and non-explosion. The ionic liquid is more thermally stable than other electrolytes and can be used as a high temperature electrolyte, but it is not easy to realize a high temperature energy device because the separator shrinks at high temperature. Here, we report a study on electrochemical supercapacitors using a composite electrolyte film that does not require a separator. The composite electrolyte is composed of thermoplastic polyurethane, ionic liquid and fumed silica nanoparticles, and it acts as a separator as well as an electrolyte. The silica nanoparticles at the optimum mass concentration of 4wt% increase the ionic conductivity of the composite electrolyte and shows a low interfacial resistance. The 5 wt% polyurethane in the composite electrolyte exhibits excellent electrochemical properties. At $175^{\circ}C$, the capacitance of the supercapacitor using our free standing composite electrolyte is 220 F/g, which is 25 times higher than that at room temperature. This study has many potential applications in the electrolyte of next generation energy storage devices.

• Tribology and Lubricants
• /
• v.40 no.3
• /
• pp.78-83
• /
• 2024

The development of eco-friendly alternative energy sources has become a global priority owing to the depletion of fossil fuels and an increase in environmental concerns. Hydrogen energy has emerged as a promising clean energy source, and hydrogen compressors play a crucial role in the storage and distribution of compressed hydrogen. However, harsh operating conditions lead to the rapid deterioration of conventional lubricants in hydrogen compressors, thereby necessitating the development of advanced lubrication technologies. This study introduces micrometer-sized silicone rubber powders as lubricant additives to enhance the lubrication performance of hydraulic oils in hydrogen compressors. We prepare silicone rubber powders by varying the ratio of the silicone rubber base to the curing agent and investigate their effects on interfacial properties, friction behavior, and wear characteristics. The findings reveal that the incorporation of silicone rubber powders positively influences the surface affinity, wettability, friction reduction, and wear resistance of the lubricants on the 304SS substrate. Moreover, we identify the optimal lubricant formulations, with a 15:1 ratio demonstrating the most effective friction reduction and a 5:1 ratio exhibiting the highest wear resistance. The controlled surface modification by the silicone rubber powder and the enhanced interfacial characteristics of the powder-containing lubricants synergistically contribute to the improved lubrication performance. These results indicate the potential of silicone rubber powder additives for the development of long-life lubrication solutions for hydrogen compressors and related applications, ultimately contributing to the advancement of sustainable energy technologies.