• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.11a
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• pp.63-64
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• 2022

In this study, the quality of mineral admixture, Comparison of blast-furnace slag(BS) and fly ash(FA)in Korea and China. In the case of BS, Korea is mainly classified into 1 type to 4 types according to the specific surface area, whereas China is classified into S105, 95, and 75 according to the activity index of 28 days of age. In the case of FA, Korea is like BS, is mainly classified into types 1 to 4 according to specific surface area, whereas China is classified into F, C (class F, class C) by ingredients and class I, II, and III according to powder and ignition loss.

• Analytical Science and Technology
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• v.18 no.1
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• pp.74-84
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• 2005

Understandings of adsorption characteristic of interface are very important in several advanced materials processes, related to NT and BT technology. Volumetric gas adsorption method, suitable for absolute measurements, is regarded as the standardized measurement technique for specific surface area. In order to verify the reliability of commercial equipments, certified reference materials (called CRM) of specific surface area are developed and evaluated its uncertainty factors by standard equipment which has traceability to SI units. Specific surface areas of developed materials are $10.72{\pm}0.46m^2g^{-1}$ for silicon nitride powders and $149.50{\pm}3.44m^2g^{-1}$ for alumina. These disseminations of CRMs would result in improved reliability chains in industrial processes, and lead eventually to contribution to productivity improvement, quality management, safety evaluation, and possibly to new material development.

• Journal of Korea Foresty Energy
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• v.21 no.2
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• pp.17-24
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• 2002

Activated carbons were prepared from pine bark by steam activation, and pore structures and specific surface areas were then investigated. Three different types of kilns were used for the activation. When the stationary-vertical-or stationary-horizontal-type kiln was used for the steam activation to prepare an activated carbon from the bark, it was not possible to produce activated carbon having high specific surface areas exceeding 1,000 $m^2／g$. Using bark powder improved the specific surface area, but it was still not high enough. When the rotary-horizontal-type kiln was used for the activation, the activated carbons prepared had high specific surface areas of more than 1,000$m^2／g$, which was similar to a commercial first-grade activated carbon. The activated carbon prepared by the rotary kiln had a wide distribution of pore size ranging from microporous to mesoporous.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.13 no.1
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• pp.15-28
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• 1987

Silica spheres were prepared by interfacial reaction method. Factors in-fluencing to the mean particle size and specific surface area of silica spheres were investigated. The experiment about the surface modification of silica spheres was carried out. It was observed that silica spheres have characteristics of the spherical shape with the vacancy in the inner side, high surface area, and reaction tendency by many silanol group. The mean particle size of silica spheres is dependent on the surfactant concentration and W/O ratio. The specific surface area is influenced by SiO2/Na2O mole ratio in sodium silicate. Silica spheres coated with titanium dioxide or zirconium dioxide improve the UV protection effect. Titanate and silane coupling agent make chemical bond with silica surface and improve the organophile and the dispersibility of silica spheres.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.15 no.6
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• pp.244-251
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• 2005

The relationship between particle size of hydro-thermally synthesized barium titanate powders (BT01, BT02, BT03, BT04, BT05) and the powder properties was investigated by means of particle size, specific surface area, zeta potential, XPS, XRD and SEM. Particle size determined by laser light scattering is closely related with specific surface area and the tetragonality (c/a) obtained from XRD. The specific surface area of the samples inversely decreased with increasing particle size except BT03 powder. BT03 sample showed higher surface area than BT04 sample of equivalent particle size, which was attributed mostly to the agglomeration of particles in terms of SEM image and XRD analysis. Zeta potential increased with increasing particle size with the exception of BT02 and BT03 which showed larger minus value of zeta potential in comparison with other BT powders. Beta potential results of BT02 and BT03 are considered to be related with the dissolution of $Ba^{2+}$ ion in these powers which was examined by XPS.

• Clean Technology
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• v.24 no.4
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• pp.287-292
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• 2018

Effect of physical property of activated carbon on its carbon dioxide adsorption was investigated for the effective control of carbon dioxide. Pinewood sawdust and coal were used as raw materials of activated carbon. Specific surface area, micropore volume and mesopore volume of the prepared activated carbons were determined, respectively. The prepared activated carbons were analyzed for their adsorption capacity of carbon dioxide. The adsorption capacity was then presented with respect to the surface area, micropore volume and mesopore volume, respectively. As a result, the specific surface area and micropore volume of both pinewood and coal activated carbon were highly related to its carbon dioxide capacity. Its mesopore volume hardly affected its carbon dioxide capacity. Preparation of activated carbon with high specific surface area and micropore volume was found to be critical to the effective control of carbon dioxide.

• Journal of Powder Materials
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• v.17 no.5
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• pp.379-384
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• 2010

In the present work, bismuth nanopowders with various particle size distributions were synthesized by controlling argon (Ar) gas flow rate and chamber pressure of a gas condensation (GC) apparatus. From the analyses of transmission electron microscopy (TEM) images and nitrogen gas adsorption results, it was found that as Ar gas flow rate increased, the specific surface area of bismuth increased and the average particles size decreased. On the other hand, as the chamber pressure increased, the specific surface area of bismuth decreased and the average particles size increased. The optimum gas flow rate and chamber pressure for the maximized electrochemical active surface area were determined to be 8 L/min and 50 torr, respectively. The bismuth nanopowders synthesized at the above condition exhibit 13.47 $m^2g^{-1}$ of specific surface area and 45.6 nm of average particles diameter.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.2
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• pp.49-56
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• 2018

The use of highly absorptive materials in cement-based materials is increasing for internal curing purpose. However, calculation of correct absorption capacity of such materials is not easy, which leads to change in the effective water-to-cement ratio of cement paste by either absorbing or releasing water. In this study, effective absorption capacity of a highly absorptive material was found using isothermal calorimetry. Moreover, the effect of specific surface area was investigated. It was found that the method was capable of finding effective water absorption capacity of activated carbon fiber. For the activated carbon fiber used in this research, the effect of specific surface area was negligible because the high BET surface area was due to micropores less than 1nm, which does not affect the rate of hydration curve. Thus, the effective absorption capacity of such materials can be found successfully using this method.

• Korean Journal of Materials Research
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• v.29 no.10
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• pp.623-630
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• 2019

Because of their excellent stability and highly specific surface area, carbon based materials have received attention as electrode materials of electrical double-layer capacitors(EDLCs). Biomass based carbon materials have been studied for electrode materials of EDLCs; these materials have low capacitance and high-rate performance. We fabricated tofu based porous activated carbon by polymer dissolution reaction and KOH activation. The activated porous carbon(APC-15), which has an optimum condition of 15 wt%, has a high specific surface area($1,296.1m^2\;g^{-1}$), an increased average pore diameter(2.3194 nm), and a high mesopore distribution(32.4 %), as well as increased surface functional groups. In addition, APC has a high specific capacitance($195F\;g^{-1}$) at low current density of $0.1A\;g^{-1}$ and excellent specific capacitance($164F\;g^{-1}$) at high current density of $2.0A\;g^{-1}$. Due to the increased specific surface area, volume ratio of mesopores, and surface functional groups, the specific capacitance and high-rate performance increased. Consequently, the tofu based activated porous carbon can be proposed as an electrode material for high-performance EDLCs.

• Journal of the Korean Ceramic Society
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• v.28 no.2
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• pp.146-152
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• 1991

Ultra fine and homogeneous (Ni0.4Zn0.6)Fe2O4 ferrite powders were prepared by direct-wet, Hydrothermal and coprecipitation methods. In case that specific surface areas of Ni-Zn ferrite powders were over 220㎡/g, 100㎡/g, 30㎡/g individually direct-wet, hydrothermal and coprecipitation methods. The Ni-Zn ferrite magnetic fluids of which Solvents were benzene or kerosene was prepared by making cation surfactant adsorbed on the surface of the (Ni0.4Zn0.6)Fe2O4. The results that measured dispersion and viscosity by making cation surfactant adsorbed were as follows. 1. The adsorption amount of Oleric acid be proportioned the specific surface area of powders. 2. The maximum amount of Oleric acid was 36wt% of dried powders which has 220㎡/g of specific surface area. 3. The stability of fluid by direct-wet synthesis emthod in benzene or kerosene solvent excellent.