• Korean Journal of Soil Science and Fertilizer
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• v.36 no.2
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• pp.86-91
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• 2003

Carbon material such as graphite and activated charcoal can promote the growth of some formsog bacteria. We examined whether this bacterial growth promoting effect can have a positive influence on field crops. Refined graphite was mixed into the standard soil used in rice cultivation. Varying soil graphite mixtures of 0.1%, 0.5% and 1% were used to cultivate rice seedling for 3 weeks. After transplanting in the filed, rice plants were cultivated for 4 months. To observe the effect of graphite(carbon material) during the cultivation of rice, we examined various different growth components in this research. During the transplanting stage, growth promoting effect of carbon was observed in the 0.1% carbon added soil. However, there were not much difference between graphite added soil and standard soil in the other stages. Rice yield was highest in the soil with 0.1% graphite.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.98-98
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• 2009

본 연구에서는 금속과 Graphite로 구성된 (100-x) Fe - x Graphite (x=40, 50, 60, 70, 80 wt%) 복합체의 기계적 특성(열팽창계수, 압축강도) 및 미세구조를 조사하였다, Fe-Grphite 복합체 제조는 각각의 Fe와 graphite 분말을 건식 혼합한 후, Hot press 사용해 온도 $1100^{\circ}C$, 압력 7ton 에서 복합체를 제조하였다. 제작된 시편은 SEM을 통하여 미세구조를 관찰하였고, Grphite 함량에 따른 열팽창계수 및 압축강도의 측정 값이 변화를 조사하였다. Graphite 함량이 증가함에 따라 열팽창계수는 감소하였으며 또한 압축강도도 감소하였다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.583-584
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• 2012

• Corrosion Science and Technology
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• v.8 no.1
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• pp.27-39
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• 2009

Non metallic composite materials, for example, GECM(graphite epoxy composite material) show high specific strength because of low density. These kinds of non metallic composite materials improved the structural effectiveness and operation economics. However, if these materials contacted several metals, corrosion can be arisen since non metallic composite materials have electrical conductivity. This paper dealt with galvanic corrosion between graphite epoxy composite material and several metals. Base on the electrochemical galvanic corrosion test between GECM and metals, corrosion current of carbon steel and aluminium increased with time but corrosion current of stainless steels and titanium decreased and galvanic potential increased. This behavior shows the galvanic corrosion depends upon the presence of passive film. Also, galvanic effect of GECM coupled with ferrous alloys and non-ferrous alloys was lower than that of 100% graphite, which is attributed to lower exposed area of graphite fiber in the GECM than apparent area of the GECM specimen used for the calculation of galvanic current in this work.

• Steel and Composite Structures
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• v.21 no.4
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• pp.849-862
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• 2016

This paper investigates the static buckling behaviours of Functionally Gradient Polymeric Material (FGPM) shells in the form of hemispherical segment. A new FGPM model based on experimental was considered to investigate the buckling problem of thin-walled spherical shells loaded by the external pressure. The spherical shells were formed by FGPM which was produced adding the two types of graphite powders into epoxy resin. The graphite powders were added to the epoxy resin as volume of 3, 6, 9, and 12%. Halpin-Tsai and Paul models were used to determine the elastic moduli of the parts of FGPM. The detailed static buckling analyses were performed by using finite element method. The influences of the types and volume of graphite powders on the buckling behaviour of the FGPM structures were investigated. The buckling loads of hemispherical FGPM shells based on Halpin-Tsai and Paul models were compared with those determined from the analytical solution of non-graphite condition existing for homogeneous material model. The comparisons between these material models showed that Paul model was overestimated. Besides, the critical buckling loads were predicted. The higher critical buckling loads were estimated for the PV60/65 graphite powder due to the compatible of the PV60/65 graphite powder with resin.

• Journal of Electrochemical Science and Technology
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• v.12 no.1
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• pp.74-81
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• 2021

Silicon (Si) is recognized as a promising anode material for high-energy-density lithium-ion batteries. However, under a condition of electrode comparable to commercial graphite anodes with low binder content and a high electrode density, the practical use of Si is limited due to the huge volume change associated with Si-Li alloying/de-alloying. Here, we report a novel core-shell composite, having a reversible capacity of ~ 500 mAh g-1, by forming a shell composed of a mixture of nano-Si, graphite nanosheets and a pitch carbon on a spherical natural graphite particle. The electrochemical measurements are performed using electrodes with 2 wt % styrene butadiene rubber (SBR) and 2 wt.% carboxymethyl cellulose (CMC) binder in an electrode density of ~ 1.6 g cm-3. The core-shell composites having the reversible capacity of 478 mAh g-1 shows the outstanding capacity retention of 99% after 100 cycles with the initial coulombic efficiency of 90%. The heterostructure of core-shell composites appears to be very effective in buffering the volume change of Si during cycling.

• Journal of Power System Engineering
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• v.10 no.1
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• pp.52-59
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• 2006

Graphite is well known as a material which has high-temperature thermostable property, chemical resistance against acid and alkaline state also is very easy to environment. Nowadays the need of graphite product is increasing rapidly because of its advantages. In this paper, the mechanical property of newly developed graphite products with high density is investigated with especially in compression test. I introduced the graphite specimens for this study by NGF method with two expandable graphite and compared to the specimens of commercial graphite sheet from expanded graphite which made by the rolling process. I investigated the characteristics of these materials by measuring specific weight, hardness, compressive strength and investigating structures by SEM, It is verified that the graphite products with NGF method has superior properties for using gasket materials than that of commercial graphite sheet.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.5
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• pp.66-71
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• 1998

It is required the superior materials for the parts of machines or structures, which could be endurable in severe load and environment. According to advancement of casting technology, nodular graphite cast iron is used as suitable for such condition. But nodular graphite cast iron is scattering of fatigue strength and low reliability. Therefore in this study, the effect of matrix structure and number of nodular graphite on the initiation of fatigue crack and fatigue strength. It was found that the material which has relatively high ferrite volume fraction was more easily cracked than other materials and fatigue limit was low. The material which has not found pinhole on the surface, the crack was initiated in graphite went through ferrite and propagated into through graphite, but separated graphite and ferrite grain boundary and combined with other cracks to fro large one.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.8
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• pp.505-509
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• 2016

We have investigated the characteristics of amorphous silicon (a-Si) thin-film solar cell by inserting barrier layer. The conversion efficiency of a-Si thin-film solar cells on graphite substrate shows nearly zero because of the surface roughness of the graphite substrate. To enhance the performance of solar cells, the surface morphology of the back side were modified by changing the barrier layer on graphite. The surface roughness of graphite substrate with the barrier layer grown by plasma enhanced chemical vapor deposition (PECVD) reduced from ~2 um to ~75 nm. In this study, the combination of the barrier layer on graphite substrate is important to increase solar cell efficiency. We achieved ~ 7.8% cell efficiency for an a-Si thin-film solar cell on graphite substrate with SiNx/SiOx stack barrier layer.

• Journal of Power System Engineering
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• v.9 no.4
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• pp.148-154
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• 2005

Thermostable property is one of most important characteristics of graphite. Commercial graphites sheet from expanded graphite is using for high-temperature elements. Nowadays the new plant with high performance is developed in field of chemical industries, so the need of graphites is increasing rapidly. In this paper, the thermostable properties of newly developed graphite products with high density is investigated. I introduced the graphite material which developed for these heat tests by NGF method in order to test thermostable properties by comparing to the results of the commercial graphite sheet from expanded graphite in same condition. Through measuring the weight reducing ratio with various specimens in some conditions, I investigated the thermostable characteristics of these materials. It is verified that the graphite products by NGF method has almost same or superior thermostable properties comparing with that of commercial graphite sheet. Also the graphite products by NGF method have possibility of being better in thermostable properties.