• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.13 no.2
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• pp.285-289
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• 1995

This paper describes the determination of geoid using height data measured by GPS and Spirit Levelling. The GPS data of the 88 stations were used to determine the geoid undulation (N) which can be easily obtained by subtracting the orthometric height(H) from the ellipsoidal height(h). From the geoid undulation (N) calculated at each station mentioned above, geoid plots with a contour interval of 0.25 m were drawn using two interpolation methods. The following interpolation methods were applied and compared with each other: Minimum Curvature Method and Least Squares Fitted Plane. Comparison between geometric geoid and gravimetric geoid undulation by FFT technique was carried out.

• Journal of Integrative Natural Science
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• v.3 no.4
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• pp.210-214
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• 2010

Relationship between etch current and morphology and porosity of porous silicon (PS) has been investigated. The gravimetric method is applied to measured the porosity of PS. As the current density increase, the silicon dissolution rate increases, resulting in a higher porosity and etching rate. The result shows that linear dependence of PS porosity and etching rate as a function of current density. The morphology of porous silicon was investigated by using cold field emission scanning electron micrograph (FE-SEM). The size of pores formed during anodization is predominantly controlled by the current density, with an increase in the pore size corresponding to an increase in the current density.

• Bulletin of the Korean Chemical Society
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• v.32 no.1
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• pp.117-121
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• 2011

Size-controlled Ag nanoparticles (NPs) were prepared from the decomposition of Ag(I) carboxylates using ethanolamine derivatives as a reducing agent without an additional stabilizing agent. The size of the Ag NPs with a narrow size distribution (sub-10 nm to ca. 40 nm) was controlled precisely by varying the processing parameters, such as the type of reducing agent and the chain length of the carboxylate in the Ag(I) carboxylate. The optical properties, surface composition and crystallinity of the Ag NPs were characterized by ultraviolet-visible spectroscopy, gas chromatography-mass spectrometry, thermal gravimetric analysis, transmission electron microscopy and X-ray diffraction.

• Korean Journal of Food Science and Technology
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• v.37 no.2
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• pp.301-303
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• 2005

Effort of rice resistant starch (RS) content on glucose blood level of normal Subject was examined using Suwon 464 and Ilpum, haying different RS contents. Enzymatic-gravimetric method showed RS contents of Suwon 464 and Ilpum were 16.3 and 0.7%, respectively. Both rice varieties, each containing 50g carbohydrate, were pressure-cooked and fed to ten healthy male volunteers after overnight fast. Significant difference was observed in 60 min blood glucose levels of Suwon 464 and Ilpum after meal, showing $90.3{\pm}4.8$ and $111.6{\pm}2.7mg/dl$, respectively (p<0.01).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.207-208
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• 2007

Recently, high performance microelectronic devices are designed in multi-layer structure in order to make dense wiring of metal conductors in compact size. Imprint lithography have received significant attention due to an alternative technology for photolithography on such devices. In this work, we synthesized dielectric composite materials based on epoxy resin, and investigated their thermal stabilities and dynamic mechanical properties for thermal imprint lithography. In order to enhance the mechanical properties and toughness of dielectric material, various modified polyetherimide(PEI) was applied in the resin system. Curing behaviours, thermal stabilities, and dynamic mechanical properties of the dielectric materials cured with various conditions were studied using dynamic differential scanning calorimetry (DSC), thermo gravimetric analysis (TGA), and Universal Test Method (INSTRON).

• Bulletin of the Korean Chemical Society
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• v.21 no.8
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• pp.817-822
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• 2000

Crack-free hard coating siIica films were prepared by sol-gel processfrom twokinds of silicon alkoxide (tetra-ethoxysilane and methyltrimethoxysilane) and two kinds of alcohol (methanol and isopropyl alcohol) with an acid catalyst,acetic acid. A silicate framework of the precursor solution was investigated by infrared spectros-copy (IR) in the process of hydrolysis and condensation. Theextent of the condensation in the intermediates was elucidated by gel permeation chromatography (GPC) and 29Si-NMR spectroscopy. The hard coating films werecharacterized by IR,scanning electron microscope (SEM), thermo gravimetric analyzer (TGA) and dif-ferential scanning calroimeter (DSC). The synthetic condition for the crack-free and transparent silica film for-mation was optimized interms of starting materials for the precursor solution as well as preparation method of the silica film.

• Journal of Electrochemical Science and Technology
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• v.10 no.2
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• pp.139-147
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• 2019

Incorporation of CuO nanoparticles during the polymerization of aniline in the presence of ammonium peroxydisulphate as an oxidizing agent and sodium salt of dodecylbenzene sulphonic acid as dopant as well as surfactant yielded water soluble CuO-PANI composite. Comparison of recorded spectra like FTIR, XRD and SEM with reported one confirm the formation of the composite. Analysis by gravimetric method exposes that the synthesized composite is having resistivity against corrosion, with slight variation in efficiency on extending the time duration up to eight hours in strong acidic condition. OCP measurement, potentiodynamic polarization and EIS studies also confirms the suppression ability of composite against corrosion. Riskless working environment could be provided by the synthesized composite during industrial cleaning process.

• Bulletin of the Korean Chemical Society
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• v.9 no.4
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• pp.244-248
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• 1988

Multilayer adsorption isotherms of nitrogen on hexagonal boron nitride, ${\gamma}$-alumina, and silica-gel powders are determined at the liquid nitrogen temperature using a gravimetric adsorption apparatus. The volume (V) of the adsorbed gas are plotted against the statistical thickness(t) of the adsorbed layer, and the t-method area are calculated from the slope of these V-t plots to compare with the BET area. A number of universal adsorption isotherms and the Frenkel-Halsey-Hill equation are used one after another in calculating the statistical thickness. The appropriateness of the FHH equation as an universal adsorption isotherm is discussed finally.

• Journal of the Korean Chemical Society
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• v.35 no.5
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• pp.539-544
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• 1991

A method to determine the thickness of silicone resin film on zinc eletroplated steel using X-ray compton scattering was investigated. On the basis of the fact that compton scattering process predominates over photoelectric absorption for the light elements such as C, H, O and Si, the compton scattered line of RhK$_{\alpha}$ was used to determine the thickness of silicone resin. In this method, the standard calibration curve for thickness determination of silicone resin film was found to be linear in the range of 0.2~5.0 ${mu}$m film thickness. The analytical results agreed well with those obtained by the gravimetric method and the accuracy was found to be 0.22 ${mu}$m.

• Journal of the Korean Chemical Society
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• v.35 no.3
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• pp.204-210
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• 1991

Multilayer adsorption isotherms of nitrogen and argon on the perovskite-type mixed oxides, synthesized by a citrate coprecipitation method, are determined at the liquid nitrogen temperature using a gravimetric adsorption apparatus. The volume of the adsorbed gas are plotted against the statistical thickness of the adsorbed layer, calculated from several universal adsorption isotherms one after another. The t-method area obtained from this plot is compared with the BET area and finally the appropriateness of universal adsorption isotherms is then discussed on the basis of the plot.