• Journal of the Korean Applied Science and Technology
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• v.28 no.2
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• pp.225-231
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• 2011

The electrochemical characteristics of electric double layer capacitor(EDLC) were investigated using various carbon materials. The physical properties such as specific surface area and mean pore size of activated carbon were analyzed by BET. The results of the activated carbon used for electrode material showed that the specific surface areas varied from 600 to 1500 $m^2$/g and mean pore sizes from 1.74 to 2.88 nm. A maximum specific capacitance of 0.30 F/$cm^2$ was obtained for the activated carbon with the highest specific surface area and ionic conductivity. Also, it was found that the electrochemical results of the cyclic charge-discharge tests were stable.

• Applied Chemistry for Engineering
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• v.35 no.2
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• pp.140-147
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• 2024

In order to increase the utilization of biomass, an electrochemical performance was considered after manufacturing a carbon anode material (SV-C) for a Setaria viridis-based lithium ion secondary battery through a heat treatment process. When the heat treatment temperature of the Setaria viridis is as low as 750 ℃, the capacitance (1003.3 mAh/g, at 0.1 C) is high due to the negative (-) charge of oxygen present on the surface attracting lithium, along with the low crystallinity and high specific surface area (126 m²/g), but the capacity retention rate is believed to be as low as 61.0% (at 500 cycles and 1 C). In addition, it was confirmed that when the heat treatment temperature increased to 1150 ℃, the carbon layer was condensed to be excellent in arrangement, and the structural defects were reduced, resulting in a significant reduction in the specific surface area (32 m²/g) of the pores. Furthermore, when the surface defects of the anode material are reduced and the crystallinity is increased, the capacity retention rate is as high as 89.7% (at 500 cycles and 1 C), but the degree of defects is small, the active point is reduced, and the specific capacity is considered to be very low at 471.7 mAh/g. In the scope of this study, it was found that in the case of the Setaria viridis-based carbon anode material manufactured according to the heat treatment temperature, the surface oxygen content and crystallinity have higher reliability on the electrochemical properties of the anode material than the specific surface area.

• Journal of the Korean Electrochemical Society
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• v.16 no.2
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• pp.85-90
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• 2013

Graphite is a commercial anode material to have the specific capacity of 372 mAh/g and the true density of 2.2 g/ml. Many effort had been pouring to find out the better material than graphite. Good candidates are silicon, tin, etc. Zinc is also a plausible candidate to have the specific capacity of 412 mAh/g and the true density of 7.14 g/ml. In this study, the Zn based anode material including indium and nickel as minor additives was synthesised. In order to get the homogeneouly mixed Zn-In-Ni composite material, the sol-gel method was used. The anode prepared by Zn-In-Ni composite material has the $1^{st}$ specific capacity of 910 mAh/g. Through prolonged charge-discharge cycling, the specific capacities were reduced to 365 (at $31^{st}$ cycle) and 378 mAh/g (at $62^{th}$ cycle). The $1^{st}$ Ah efficiency was 45% and Ah efficiencies were exhibited at the prolonged cycle.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2008.04a
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• pp.231-234
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• 2008

Each corporation isn't consistent because of offering specific information for publicity. It spends considerable labor force and time surfing of the material information and choosing need material. That's the reason it's different with material information and choice system between production and marketing corporation. Among lots of material information, some of them are used by offering material information simplify. So it is demanded necessity of reasonable material choice system. That system helps it choose a material more easily. So we studied about the information retrieval system of reasonable material choice through the study about assortment system of material information and material choice method. It's the basic study for the suggestion of reasonable material choice system. According to this study, if that system is suggested and realized, we can overcome from the system of typical and repeatable at every course of architecture during several times. It will be helpful to increase about the productivity of architecture as the minimization of time, labor, resource and cost for the material choice.

• Journal of Ginseng Research
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• v.40 no.4
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• pp.395-399
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• 2016

Background: Korean ginseng (Panax ginseng) is one of the most important medicinal plants in the Orient. Among nine cultivars of P. ginseng, Chunpoong commands a much greater market value and has been planted widely in Korea. Chunpoong has superior quality "Chunsam" ($1^{st}$ grade ginseng) when made into red ginseng. Methods: A rapid and reliable method for discriminating the Chunpoong cultivar was developed by exploiting a single nucleotide polymorphism (SNP) in the auxin repressed protein gene of nine Korean ginseng cultivars using specific primers. Results: An SNP was detected between Chunpoong and other cultivars, and modified allele-specific primers were designed from this SNP site to specifically identify the Chunpoong cultivar and P. quinquefolius via multiplex polymerase chain reaction (PCR). Conclusion: These results suggest that great impact to prevent authentication of precise Chunpoong and other cultivars using the auxin repressed protein gene. We therefore present an effective method for the authentication of the Chunpoong cultivar of P. ginseng and P. quinquefolius.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.10a
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• pp.234-237
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• 2008

It was reported that the semi-solid forming process has many advantages over the conventional forming process, such as a long die life, good mechanical properties and energy savings. It is very important, however, to control liquid segregation to gain mechanical property improvement of materials. During forming process, Rheology material has complex characteristics, thixotropic behavior. Also, difference of velocity between solid and liquid in the semi-solid state material makes a liquid segregation and specific stress variation. Therefore, it is difficult for a numerical simulation of the rheology Process to be Performed. General Plastic or fluid dynamic analysis is not suitable for the behavior of rheology material. The behavior and stress of solid particle in the rheology material during forging process is affected by viscosity, temperature and solid fraction. In this study, compression experiments of aluminum alloy were performed under each other tool shape. In addition, the dynamics behavior compare with Okano equation to Power law model which is viscosity equation.

• Korean Institute of Interior Design Journal
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• v.15 no.5 s.58
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• pp.289-297
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• 2006

This study was begun on the premise that architecture which has the definite disposition for survival even in the urban, social structure of that uncertainty and constructs specialty is biomorphic architecture. This study was made with the following four specific purposes largely. First, through the theoretical investigation of biomorphic architecture that appears in the tendency that mordern architecture develops into the architecture of do-stereotype and new form, its meaning and definition are examined. Second, the analysis of biomorphic architecture is investigated and the generation causes are applied architecturally and generate biomorphic architecture is made. Third, by analyzing the material expression characteristics of biomorphic architecture, the meaning and possibility of architecture, which expresses the vitality of organism, as the material expression characteristics of biomorphic architecture, are investigated. The material expression characteristics was deduced through the generation background of biomorphic architecture. The material expression characteristics of biomorphic architecture is the various modeling by smart-network and the response system of sensitivity poly-logue.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.289-289
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• 2007

Spinel structured $LiMn_2O_4$ is more economic and environmental friendly to be used as commercial active material for secondary battery compared to Co-oxide material active material, but spinel structure of $LiMn_2O_4$ is unstable and its capacitance decreases with increase of cycle. Therefore, the purpose of our sturdy is to improve the stability of $LiMn_2O_4$ spinel structure and increase its capacitance by using substituents or dopants. $LiMn_2O_4$ powder was synthesized by charging substituents or dopants mole fractions, and temperatures. Crystal state, structure and specific surface area of the synthesized powder were measured and also characteried electrochemically by measuring its impedance, charge-discharge capacitance and etc.

• Journal of the Korea Organic Resources Recycling Association
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• v.30 no.2
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• pp.5-15
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• 2022

In this study, heated tobacco biomass was prepared as an active material for supercapacitor device. Retrieved tobacco leaf from the heated tobacco was carbonized at various temperature(800/850/950℃). Carbonized tobacco leaf material synthesized at 850℃ exhibited the highest C/O ratio, indicating the finest carbon quality. In addition, polypyrrole was coated onto the carbonized leaf material for increasing the electrochemical performance via low-temperature polymerization method. As-synthesized carbonized leaf material at 850℃(CTL-850)-based electrode and polypyrrole-coated carbonized leaf material(CTL-850/PPy)-based electrode displayed outstanding specific capacitances of 100.2 and 155.3F g^-1 at 1 A g^-1 with opertaing window of -1.0V and 1.0V. Asymmetric supercapacitor device, assembled with CTL-850 as the negative electrode and CTL-850/PPy as the positive electrode, manifested specific capacitance of 31.1F g^-1(@1 A g^-1) with widened operating voltage window of 2.0V. Moreover, as-prepared asymmetric supercapacitor device was able to lighten up the RED Led (1.8V), suggesting the high capacitance and extension of operating voltage window. The result of this research may help to pave the new possibility toward preparing the effective energy storage device material recycling the biomass.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.9 s.174
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• pp.162-172
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• 2005

The objective of this research works is to investigate into characteristics of bending stiffness and failure for the ISB ultra-lightweight panel with internally structured material. The expanded metal with a crimped pyramid shape and woven metal are employed as an internally structured material. Through three-points bending test, the force-displacement curve and failure shape are obtained to examine the deformation pattern, characteristic data, such as maximum load, displacement at maximum load, etc, and failure pattern of the ISB panel. In addition, the influence of design parameters fur ISB panel on the specific stiffness, the specific stiffness per unit width, failure mode and failure map has been found. Finally, it has been shown that ISB containing expand metal with the crimped pyramidal shape is prefer to that containing woven metal from the view point of optimal design for ISB panel.