• Korean Chemical Engineering Research
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• v.53 no.6
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• pp.746-754
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• 2015

In this study, we investigated the effects of the temperature on the coal/biomass $char-CO_2$ gasification reaction under isothermal conditions of $700{\sim}900^{\circ}C$ using the lignite(Indonesia Eco coal) with biomass (korea cypress). Ni catalysts were impregnated on the coal by the ion-exchange method. Four kinetic models which are shrinking core model (SCM), volumetric reaction model (VRM), random pore model (RPM) and modified volumetric reaction model (MVRM) for gas-solid reaction were applied to the experimental data against the measured kinetic data. The Activation energy of Ni-coal/biomass, non-catalyst coal/biomass $Char-CO_2$ gasification was calculated from the Arrhenius equation.

• Korean Chemical Engineering Research
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• v.55 no.1
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• pp.99-106
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• 2017

In this study, mixed catalytic char gasification of Indonesia low-rank coal Kideco was investigated under nitrogen atmosphere and isothermal conditions at a fixed reactor. The effects of the temperature were investigated at various temperature (700, 750, 800, $850^{\circ}C$). The effects of blend ratio of catalysts ($K_2CO_3$, Ni) were investigated with different blend ratios (1:9, 3:7, 5:5, 7:3 and 9:1). The sample was prepared by mixing with $K_2CO_3$ physically and by ionexchange method with Ni. The data from thermogravimetric analyzer and gas chromatography were applied to four gassolid reaction kinetic models including shrinking core model, volumetric reaction model, random pore model and modified volumetric reaction model.

• Current Optics and Photonics
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• v.6 no.6
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• pp.550-564
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• 2022

Optical microscopy is a useful tool for study in the biological sciences. With an optical microscope, we can observe the micro world of life such as tissues, cells, and proteins. A fluorescent dye or a fluorescent protein provides an opportunity to mark a specific target in the crowd of biological samples, so that an image of a specific target can be observed by an optical microscope. The optical microscope, however, is constrained in resolution due to diffraction limit. Super-resolution microscopy made a breakthrough with this diffraction limit. Using a super-resolution microscope, many biomolecules are observed beyond the diffraction limit in cells. In the case of volumetric imaging, the super-resolution techniques are only applied to a limited area due to long imaging time, multiple scattering of photons, and sample-induced aberration in deep tissue. In this article, we review recent advances in super-resolution microscopy for volumetric imaging. The super-resolution techniques have been integrated with various modalities, such as a line-scan confocal microscope, a spinning disk confocal microscope, a light sheet microscope, and point spread function engineering. Super-resolution microscopy combined with adaptive optics by compensating for wave distortions is a promising method for deep tissue imaging and biomedical applications.

• The Journal of Korean Academy of Prosthodontics
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• v.36 no.3
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• pp.453-467
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• 1998

This study helps to clarify conflicting reports by comparing the physical properties and accuracy of complete denture processed by the pack and press technique, continuous- pressure injection technique(SR-Ivocap system) and Mark press technique. The 6 different specimens have been evaluated using the SEM, Impact test, DSC (Differential Scanning Calorimetry) and DMTA (Dynamic Mechanical Thermal Analysis). Each sample was made of SR-Ivocap resin and QC-20 resin by different processing methods. The results were as follows ; 1. As the result of the observation on the fracture surface of resin by use of SEM, sample SR-Ivocap resin cured by continuous pressure injection method showed the most homogeneous structure. This is why molecules in SR-Ivocap resin have no orientation. 2. As the result of the Impact test in order to measure the deformity, fracture energy and impact resistance of resin, the samples with QC-20 acrylic resin and SR-Ivocap resin cured by continuous pressure injection method were exellent. 3. In consequence of measuring ${\alpha}$-glass transition temperature by use of DSC on the basis of temperature change, the glass transition temperatures of sample QC-20 resin cured by pack and press method and sample SR-Ivocap resin cured by continuous pressure injection method were very similar. Thus volumetric stability could not be evaluated only by glass transition temperature. 4. In comparing volumetric stability data by DMTA, the glass transition temperature(Tg) showed $137.88^{\circ}C$ at sample QC-20 resin cured by pack and press method and $139.78^{\circ}C$ at sample SR-Ivocap resin cured by continuous pressure injection method. Therefore sample SR-Ivocap resin cured by continuous pressure injection method seems to be superior to sample QC-20 resin cured by pack and press method in the dimensional stability at high temperature. 5. In comparing storage modulus data by DMTA, the storage modulus of sample SR-Ivocap resin cured by continuous pressure injection method was higher than that of sample QC-20 resin cured by pack and press method. So. sample SR-Ivocap resin cured by continuous pressure injection method seems to be superior to sample QC-20 resin cured by pack and press method in impact strength.

• Applied Biological Chemistry
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• v.1
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• pp.26-33
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• 1960

Organic mercurial fungicides, for seed treatments and dust formulations, has been increasingly used by farmers. Evaluation of the purity of organic mercurial fungicides has been performed by precipitation method at this laboratory. There are several methods for the an alyses of organic mercuric formulation, among which are (1) Precipitation met hod, (2) Volatilization method, (3) Volumetric method, and (4) Dithizon method. These methods, however, show some deffects in specificity (differentiation of organic form) and quantitativity. Polarography applied for the estimation of phenyl mercuric acetate was found to be simple, rapid and accurate. Tile fundamental method of polarography arid accuracy of analysis are discussed statistically and a satisfactory results was obtained.

• Journal of Biomedical Engineering Research
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• v.27 no.3
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• pp.110-116
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• 2006

Finite element method (FEM) provides several advantages over other numerical methods such as boundary element method, since it allows truly volumetric analysis and incorporation of realistic electrical conductivity values. Finite element mesh generation is the first requirement in such in FEM to represent the volumetric domain of interest with numerous finite elements accurately. However, conventional mesh generators and approaches offered by commercial packages do not generate meshes that are content-adaptive to the contents of given images. In this paper, we present software that has been implemented to generate content-adaptive finite element meshes (cMESHes) based on the contents of MR images. The software offers various computational tools for cMESH generation from multi-slice MR images. The software named as the Content-adaptive FE Mesh Generation Toolbox runs under the commercially available technical computation software called Matlab. The major routines in the toolbox include anisotropic filtering of MR images, feature map generation, content-adaptive node generation, Delaunay tessellation, and MRI segmentation for the head conductivity modeling. The presented tools should be useful to researchers who wish to generate efficient mesh models from a set of MR images. The toolbox is available upon request made to the Functional and Metabolic Imaging Center or Bio-imaging Laboratory at Kyung Hee University in Korea.

• Journal of Ocean Engineering and Technology
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• v.30 no.4
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• pp.235-242
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• 2016

In general, ship hull form design is carried out in two stages. In the first stage, the longitudinal variation of the sectional area curves is adapted from a similar mother ship to determine the volume distribution in ships. At this design stage, the initial design conditions of displacement, longitudinal center of buoyancy, etc. are satisfied and the global hydrodynamic properties of the structure are optimized. The second stage includes the local designing of the sectional forms. Sectional forms are related to the local pressure resistance in the fore- and aft-body shapes, cargo boundaries, interaction between the hull and propeller, etc. These relationships indicate that the hull sections need to be optimized in order to minimize the local resistance. The volumetric balanced (VOB) variation of ship hull forms has been suggested by Kim (2013) as a generalized, systematic variation method for determining the sectional area curves in hull form design. This method is characterized by form parameters and is based on an optimization technique. This paper emphasizes on an extensional function of the VOB considering a geometrical wave profile. We select a container ship and an LNG carrier to demonstrate the applicability of the proposed technique. Through analysis, we confirm that the VOB method, considering the geometrical wave profile, can be used as an efficient tool in the hull form design for ships.

• The Journal of Engineering Geology
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• v.20 no.1
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• pp.89-100
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• 2010

Although various methods for determination of damage threshold in rock have been suggested, clear damage thresholds were determined by some methods, but different thresholds were measured by other methods. We determined the damage thresholds in Hangdeung granite using all the methods suggested, and investigated the best methods, applicability and errors of each method. The crack initiation threshold and the crack damage threshold which are important in investigation of characteristics of crack development and failure were verified by field strength ratio method and long-term constant load test. The crack closure stress and the crack initiation stress were 57.5 MPa and 77.6 MPa, and the most exact values were yielded by crack volumetric strain. The secondary crack initiation stress was 90.6 MPa and AE event count and AE event count rate were the effective methods. The volumetric stiffness, AE event count and AE event count rate were the most effective methods for determination of crack coalescence threshold and crack coalescence stress was 110.3 MPa. The crack damage stress was 127.5 MPa and was measured correctly by volumetric stiffness and AE event count rate. The ratio between crack initiation stress and uniaxial compressive strength was 0.47 which was very similar with the FSR value of 0.46. The ratio between crack damage stress and uniaxial compressive strength was almost the same as the ratio between long-term strength and uniaxial compressive strength, indicating that the crack initiation stress and the crack damage stress measured were correct.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.12
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• pp.1383-1389
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• 2011

The current study focuses on the consistent analysis of heat transfer in multichannel volumetric solar receivers used for concentrating solar power. Changes in the properties of the absorbing material and channel dimensions are considered in an optical model based on the Monte Carlo ray-tracing method and in a one-dimensional heat transfer model that includes conduction, convection, and radiation. The optical model results show that most of the solar radiation energy is absorbed within a very small channel length of around 15 mm because of the large length-to-radius ratio. Classification of radiation losses reveals that at low absorptivity, increased reflection losses cause reduction of the receiver efficiency, notwithstanding the decrease in the emission loss. As the average temperature increases because of the large channel radius or small mass flow rate, both emission and reflection losses increase but the effect of emission losses prevails.

• Journal of the Korean Society of Radiology
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• v.16 no.1
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• pp.53-59
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• 2022

DEXA, as the standard areal bone mineral density (aBMD) measurement method, often shows an insuficient correlation between aBMDs of the measured bones and referring bones and is inaccurate due to the mass effect. In contrast, quantitative computer tomography (QCT), as a volumetric BMD (vBMD) measurement method, is being advanced so that it uses less radiation before, owing to improved CT device and computer imaging technology. Because dual-energy CTs can modulate the image signals showing tumor or specific chemicals as well as the ability to measure vBMD, they are expanding their application. For pre-checking vBMD of surgeon-specific bone volume at implantation candidate sites, a finite element creation-based local vBMD measurement technique was developed. The local vBMD measurement function for surgeon-specific shape volumes will be added to clinical imaging systems.