• Korean Journal of Soil Science and Fertilizer
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• v.41 no.5
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• pp.310-317
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• 2008

This study was carried out to investigate the factors of desalinization of the rainfall interception culture soils of Rubus sp. in Gochang-gun, Jeollabuk-do. Soil samples were collected from 85 different sites of the rainfall interception culture soils of Rubus sp. in Gochang-gun, Jeollabuk-do. The electrical conductivity in paste saturation of rainfall interception culture soils ranged from $1.0\sim28.4dS\;m^{-1}$ (average: $4.8dS\;m^{-1}$) and salt affected soil which EC was higher than $4dS\;m^{-1}$, covered nearly 55% of all field surveyed. Salts in rainfall interception culture soils were accumulated by increasing the cultivation period. Electrical conductivity in rainfall interception culture soils was positively correlated with water soluble anions such as chloride ion ($r=0.85^{**}$), nitrate ion ($r=0.94^{**}$), phosphate ion ($r=0.88^{**}$), and sulfate ion ($r=0.84^{**}$), respectively. As a result of desalinization experiments carried out by water management practices, the rinsing method was more effective than leaching method.

• Journal of the Korean Chemical Society
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• v.31 no.6
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• pp.498-502
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• 1987

Electrical conductivities of $(ZrO_2)_x-(Tm_2O_3)_y$ systems containing 1, 3 and 5mol% of $ZrO_2$ have been measured as a function of temperature and of oxygen partial pressure at temperatures from 600 to 1,100$^{\circ}$C and oxygen partial pressures from $10^{-5}$ to $2{\times}10^{-1}atm$. Plots of log conductivity vs. 1/T are found to be linear and average activation energy is 1.51 eV. The electrical conductivity dependences on PO$_2$ are different at two temperature regions, indicating ${\sigma}{\alpha}PO_2^{1/5.3}$ and ${\sigma}{\alpha}PO_2^{1/10.7}$ at high-and low-temperature regions, respectively. The defect of $(ZrO_2)_x-(Tm_2O_3)_y$ system is $V_{Tm}^{'''}$ and an electron hole is suggested as a carrier at high temperature region. At low temperature region, a mixed ionic and hole conduction is reasonable.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.9
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• pp.2181-2193
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• 1995

The effective elasticity and conduction of composite materials containing arbitrarily oriented multiple phases has been analyzed using the concept of orientation-dependent average fields and concentration factors. The analysis provided closed form expressions for the effective stiffnesses and conductivities. Under the prescribed boundary conditions, the concentration factors were evaluated by the equivalent inclusion principle, through which the interaction between various phases is approximated by the Mori-Tanaka mean-field approximation. SiC particulate(SiC$_{p}$) reinforce aluminum(Al) matrix composites were fabricated and their elastic constants and electrical conductivities were measured together with a careful study of their microstructure. The measured properties showed a systematic anisotropy and this behavior could be attributed to the preferred orientation of SiC$_{p}$. The theoretical model developed was applied to the computation of the anisotropic properties of these composites. Both two-phase and three-phase composites were considered based on the microstructural information. The SiC$_{p}$ was modeled as an ellipsoid with planar random orientation distribution in the extruded Al/SiC$_{p}$ composites. The effect of extraneous phase such as intermetallic compounds was also investigated.tigated.

• Korean Journal of Ecology and Environment
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• v.36 no.2 s.103
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• pp.200-207
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• 2003

This research was conducted to investigate the influences caused by solifluction soil on the physicochemistry of stream water quality in the riparian area: four points of the northeastern side slopes part of the Bughansan National Park from March to May of 2002. The average pH of stream water was relatively high with the influenced of solifluction soil. The average electrical conductivity of upstream water was 2.1${\sim}$2.8 times lower than that in downstream water. pH and amount of anion ($Cl^-,\;N0_3\;^-, So_4\;^{2-}$) of stream water was correlated under the effect of solifluction soil.

• Applied Chemistry for Engineering
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• v.29 no.2
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• pp.162-167
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• 2018

The effect of the average particle size and shape of silver nanoparticles for the transparent conductive film (TCF) was studied. Optical and electrical properties of silver conductive lines coated on the polyethylene terephthalate (PET) film was also measured. Silver nanoparticles produced by Ag-CM, Ag-ME, Ag-EE methods showed an excellent conductivity compared to those produced by Ag-EB, Ag-CR and Ag-PL methods, but a little difference in the transparency. In the case of the former three silver nanoparticles, the average particle size was about 80 nm or less and the size was uniform. For the latter case, the severe agglomeration phenomena of particles was observed and the average particle size was 100 nm or more. This result was consistent with the result of the uniformity of the pattern shape and thickness on conductive line patterns observed by SEM. Therefore, it was confirmed that the electrical characteristics could be obtained when the average particle size of silver nanoparticles is smaller and the uniformity of the particles is maintained.

• The Plant Pathology Journal
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• v.26 no.2
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• pp.198-202
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• 2010

A study was conducted to find out the relationship of physico-chemical properties (viz. organic carbon(OC), pH, electrical conductivity, nitrogen, phosphorus and potassium content) of ginger growing soil with incidence percentage of rhizome rot and wilt disease complex of ginger. Organic carbon content and pH of the ginger soil contributed significantly (93%) in the prediction of ginger rhizome rot and wilt disease complex incidence with negative correlation. Soil having weak acidic reaction with OC percent greater than 2.25 was observed to have the lower average incidence of the disease.

• Carbon letters
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• v.12 no.2
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• pp.70-80
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• 2011

Two pitches with different average molecular structures were electrospun and compared in terms of the properties of their fibers after oxidative stabilization, carbonization, and activation. The precursor with a higher molecular weight and greater content of aliphatic groups (Pitch A) resulted in better solubility and spinnability compared to that with a lower molecular weight and lower aliphatic group content (Pitch B). The electrical conductivity of the carbon fiber web from Pitch A of 67 S/cm was higher than that from Pitch B of 52 S/cm. The carbon fiber web based on Pitch A was activated more readily with lower activation energy, resulting in a higher specific surface area compared to the carbon fiber based on Pitch B (Pitch A, 2053 $m^2/g$; Pitch B, 1374 $m^2/g$).

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.226-226
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• 2003

The Commercial LiCoO$_2$ particles, which were 7.7${\mu}{\textrm}{m}$ in average diameter, were coated with $Al_2$O$_3$ by a gas suspension spray coating method. The coating amount of $Al_2$O$_3$ on the surface of LiCoO$_2$ was varied from 0.1 to 2 wt.% and compared their electrochemical characteristics with those of bare LiCoO$_2$. $Al_2$O$_3$ coating on the surface of LiCoO$_2$ increased surface area and electrical conductivity, and showed the better cycle and thermal stability even at the higher voltage. The observed optimum A1$_2$O$_3$ coating amount that exhibited the highest capacity retention was 0.2 wt.%.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.453-454
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• 2011

With the transmission line the ratio of lightning breakdown the while whole breaking down is occupying a high share with average 72%, is a tendency which increases continuously. In order decreasing the back flashover faults from like this lightning breakdown, it is very important to maintain grounding resistance of tower below target. In this paper, we synthetically analyzed the grounding resistance reduction effect of tower foundation and standard ground connection from construction site, and investigated efficiency for ways to increase the length of counter poise and expand the size of conductivity concrete materials.

• Carbon letters
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• v.15 no.3
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• pp.162-170
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• 2014

Pitch is an attractive raw material for carbon fiber precursors due to its low cost stemming from its availability as a residue of coking and petroleum processes. Ford Motor Company reported a carbon fiber target price of $11.0/kg by using a fast cycle-time manufacturing method with carbon fiber in an inexpensive format, allowing for an average retail price of gasoline of $3.58/gallon. They also recommended the use of carbon fiber with strength of 1700 MPa, modulus of 170 GPa, and 1.5% elongation. This study introduced a ca. $5.5{\mu}m$ carbon fiber with 2000 MPa tensile strength obtained from a precursor through simple distillation of petroleum residue. Petroleum pitch based carbon nanofibers prepared via electrospinning were characterized and potential applications were introduced on the basis of their large specific surface area and relatively high electrical conductivity.