• Journal of the Korean Applied Science and Technology
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• v.32 no.2
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• pp.215-225
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• 2015

Recently, the importance of energy saving and alternative energy is significantly increasing due to energy depletion and the phase change material (PCM) research for saving energy is also actively investigating. In this research, the membrane emulsification using SPG membrane was used to make various microencapsulated phase change material (MPCM) particles which were comprised of $Rubitherms^{(R)}$ (RT-21 and RT-24) core and silica coating. We investigated the pressure of the dispersion phase, the concentration of surfactant, and the ratio of $Rubitherm^{(R)}$ and silica to prepare various MPCM particles. The DSC and TGA were used to examine the heat stability and latent heat properties. Also, PSA, SEM, and optical microscopy were used to confirm the size of $Rubitherm^{(R)}$ particles and the thickness of silica shell. The average of particle size was $7-8{\mu}m$. And, FT-IR was also used to enforce the qualitative analysis. Finally, the MPCM particles obtained from membrane emulsification showed monodispersed size distribution and the heat stability and latent heat were kept up to 80% compared to pure $Rubitherm^{(R)}$. So, it can be effectively used for wallpaper, buildings and interior products for energy saving as PCMs.

• Applied Chemistry for Engineering
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• v.26 no.4
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• pp.400-405
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• 2015

Traditional anti-reflective (AR) coating films prepared using tetraethylorthosilicate (TEOS) as a precursor absorbs water easily in addition to having a weak abrasion resistance. To improve the transmittance, hydrophobicity and abrasion resistance of AR coating film, various AR coating films were prepared using methyltrimethoxysilane (MTMS) as a precursor in addition to introducing a fluoroalkylsilane, acid catalyst, base catalyst and acid-base two step catalyst. The prepared AR coating films were then characterized by UV-Vis spectroscopy, contact angle analyzer, atomic force microscope (AFM), pencil scratch hardness test and cross-cut test. As a result, the transmittance of bare glass was 90.5%, while that of AR coating glass increased to 94.8% at curing temperature of $300^{\circ}C$. When the fluoroalkylsilane was added, the water contact angle of AR coating film increased from $96.3^{\circ}$ to $108^{\circ}$, indicating that the hydrophobicity of the film was greatly improved. The abrasion resistance of AR coating film was also improved by the acid catalyst, whereas the transmittance increased by the base catalyst. In the case of AR coating film prepared using an acid-base two step catalyzed reaction, both the transmittance and abrasion resistance of the film was synergistically enhanced as compared with those of AR coating films prepared without introduction of a catalyst.

• Applied Chemistry for Engineering
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• v.23 no.5
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• pp.440-444
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• 2012

In this work, a semi-carbonized wood chip (SC-WC) was prepared by heat-treatment at low carbonization temperature. The pyrolysis characterization and heating value of the SC-WC at different heat-treatment temperature were evaluated. The pyrolysis characterization and heating value of the SC-WC were determined using thermal gravimetric analyzer (TGA) in $N_{2}$ atmosphere and calorimeter, respectively. From the TGA results, the thermal decomposition reaction of the SC-WC treated at by low temperature was similar to pure wood chip and the reaction was most actively occurred in the range of $200^{\circ}C$ to $400^{\circ}C$, whereas the initial thermal decomposition temperature of the SC-WC increased with the increasing heat-treatment temperature. In addition, the heating value of the SC-WC showed a similar trend as to the decamposition temperature behavior. This is probably attributed to increased carbon content of SC-WC by the localized carbonization of the wood chip which consisted of cellulose, hemi-cellulose, and lignin.

• Korean Journal of Clinical Laboratory Science
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• v.39 no.1
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• pp.31-36
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• 2007

The purpose of the clinically reportable range (CRR) in clinical chemistry is to estimate linearity in working range. The reportable range includes all results that may be reliably reported, and embraces two types of ranges: the analytical measurement range (AMR) is the range of analyte values that a method can directly measure on the specimen without any dilution, concentration, or other pretreatment not part of the usual assay process. CAP and JCAHO require linearity on analyzers every six months. The clinically reportable range is the range of analyte values that a method can measure, allowing for specimen dilution, concentration, or other pretreatment used to extend the direct analytical measurement range. The AMR cannot exceed the manufacturer's limits. Establishing AMR is easily accomplished with Calibration Verification Assessment and experimental Linearity. For example: The manufacturer states that the limits of the AST on their instrument are 0-1100. The lowest level that could be verified is 2. The upper level is 1241. The verified AMR of the instrument is 2-1241. The lower limit of the range is 2, because that is the lowest level that could be verified by the laboratory. The laboratory could not use the manufacturer's lower limit of 2 because they have not proven that the instrument values below 2 are valid. The upper limit of the range is 1241, because although the lab has shown that the instrument is linear to 1241, the manufacturer does not make that claim. The laboratory needs to demonstrate the accuracy and precision of the analyzer, as well the validation of the patient AMR. Linearity requirements have been eliminated from the CLIA regulations and from the CAP inspection criteria, however, many inspectors continue to feel that linearity studies are a part of good lab practice and should be encouraged. If a lab chooses to continue linearity studies, these studies must fully comply with the calibration/calibration verification requirements of CLIA and/or CAP. The results of lower limit and upper limit of clinically reportable range were total protein (2.1 - 79.9), albumin (1.3 - 39), total bilirubin (0.2 - 106.2), alkaline phosphatase (13 - 6928.2), aspartate aminotransferase (24 - 7446), alanine aminotransferase (13 - 6724.2), gamma glutamyl transpeptidase (16.64 - 9904.2), creatine kinase (15.26 - 4723.8), lactate dehydrogenase (127.66 - 13231.8), creatinine (0.4 - 129.6), blood urea nitrogen (8.67 - 925.8), uric acid (1.6 - 151.2), total cholesterol (48.52 - 3162), triglycerides (36.91 - 3367.8), glucose (31 - 4218), amylase (21 - 6694.2), calcium (3.1 - 118.2), inorganic phosphorus (1.11 - 108), HDL (11.74 - 666), NA (58.3 - 1800), K (1.0 - 69.6), CL (38 - 1230).

• Applied Chemistry for Engineering
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• v.21 no.3
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• pp.311-316
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• 2010

This study aimed to prepare antimony-doped tin oxide (ATO) dispersion with high stability. The methods to achieve this goal were sought by investigating the changes of ATO particle size, size distribution, dispersion property as wet ball milling treatment time increased. And the changes of wet ball milled ATO dispersion property were also investigated, as pH increased. The changes of ATO particle size and size distribution, according to wet ball milling treatment time were evaluated with laser diffraction particle size analyzer and scanning electron microscope (SEM). The changes of ATO dispersion property, as wet ball milling treatment time and pH increased, were evaluated with zeta potential analysis and Turbiscan. By 60 min wet ball milling treatment time, ATO particle size decreased and size distribution became narrower, as the treatment time increased. After 60 min milling, the ATO particle size decreased to less than 30% of the initial size and the size distribution was narrowed to $0.1{\sim}5{\mu}m$ from $1{\sim}35{\mu}m$. However, more than 60 min milling, ATO particles aggregated and the particle size increased. ATO dispersion stability also increased as the treatment time and pH increased because the reduced particle size increased particle surface energy and repulsion between particles and the increased pH enhanced particle surface ionization. Hence, after proper length of wet ball milling treatment, highly stable ATO dispersion can be prepared, as increasing pH of the dispersion.

• Applied Chemistry for Engineering
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• v.30 no.3
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• pp.358-364
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• 2019

To improve the optical characteristics and antifouling of anti-reflective coating (AR) films, various AR coating films were prepared by varying the mixing ratio of tetraethylorthosilicate (TEOS)/base and methyltrimethoxysilane (MTMS)/acid hybrid solution. Prepared AR coating films were characterized by UV-Vis spectroscopy, contact angle analyzer, atomic force microscope (AFM), FT-IR and pencil scratch hardness test. In an AR coating film that prepared from the hybrid solution with a 10 wt% MTMS/acid solution, the glass substrate showed an excellent optical property (97.2% transmittance), good antifouling ($121^{\circ}$ water contact angle and $90^{\circ}\;CH_2I_2$ contact angle) and moderate mechanical strength (pencil hardness of 4 H). In particular, it is considered that the good antifouling was due to the well dispersion of the methyl group ($-CH_3$), derived from a small amount of MTMS/acid solution in the hybrid solution, on the substrate surface. From results of the pencil hardness test, the mechanical strength of AR coating film was improved as the content of MTMS/acid solution increased.

• Applied Chemistry for Engineering
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• v.16 no.5
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• pp.628-634
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• 2005

Zirconia-alumina polymer precursor was prepared from zirconium acetylacetonate (ZA). paluminium nitrate (AN), polyethylene glycol (PEG), and ethyl alcohol via an organic-inorganic solution technique. The thermal properties and viscosity of the polymer precursor were measured by differential scanning calorimetry (DSC), thermograbimetric analyzer (TGA), and dynamic viscometer. The vigorous exothermic reaction with volume expansion occurred at $140^{\circ}C$. The volume expansion was caused by abrupt decomposition of the organic group in metal compounds and the metal ions-PEG reaction. The evidences for these reactions were confirmed by FT-IR and $^{13}C$ solid NMR results. The peak intensity at N-O, O-H and C=C decreased with increasing temperature. This indicated that the decomposition of metal compounds and the metal ions-PEG reaction occurred during the vigorous exothermic reaction. At $800^{\circ}C$ for 2 h, the porous powders transformed to the crystalline $ZrO_2-Al_2O_3$ composites.

• Applied Chemistry for Engineering
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• v.17 no.2
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• pp.132-137
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• 2006

Polyurethane acrylate hybrid emulsions were prepared by seeded polymerization techniques. In the synthesis, seeded polyurethane dispersion containing a carboxylic group was used to endow hydrophilicity to the hybrid emulsion and various acrylates such as methyl methacrylate (MMA), 2-hydroxy ethylmethacrylate (2-HEMA), n-butyl acrylate (n-BA) and acrylic acid (AAc) were used to endow hydrophobicity. The particle size and distribution of various emulsion particles such as polyurethane acrylate hybrid emulsion, polyurethane dispersion homopolymer, acrylate emulsion, and physical blending emulsion were measured by a particle size analyzer. The average particle size of hybrid emulsion was greater than physical blending emulsion. And tensile strength, 100% modulus, elongation, and swelling properties of the polyurethane acrylate hybrid emulsion were studied and compared with those of polyurethane homopolymer, acrylate emulsion, and physically blended compositor, respectively. To improve chemical and physical resistance, this paper review a melamine hardener and compares it for effects on the physical properties of cured coating.

• Korean Journal of Materials Research
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• v.22 no.6
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• pp.316-320
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• 2012

$Co_3O_4$, $Al_2O_3$ and $Co_3O_4$/$Al_2O_3$ mesoporous powders were prepared by a sol-gel method with starting matierals of aluminum isopropoxide and cobalt (II) nitrate. A P123 template is employed as an active organic additive for improving the specific surface area of the mixed oxide by forming surfactant micelles. A transition metal cobalt oxide supported on alumina with and without P123 was tested to find the most active and selective conditions as a heterogeneous catalyst in the reaction of styrene epoxidation. A bBlock copolymer-P123 template was added to the staring materials to control physical and chemical properties. The properties of $Co_3O_4$/$Al_2O_3$ powder with and without P123 were characterized using an X-ray diffractometer (XRD), a Field-Emission Scanning Electron Microscope (FE-SEM), a Bruner-Emmertt-Teller (BET) surface analyzer, and $^{27}Al$ MAS NMR spectroscopy. Powders with and without P123 were compared in catalytic tests. The catalytic activity and selectivity were monitored by GC/MS, $^1H$, and $^{13}C$-NMR spectroscopy. The performance for the reaction of epoxidation of styrene was observed to be in the following order: [$Co_3O_4$/$Al_2O_3$ with P123-1173 K > $Co_3O_4$/$Al_2O_3$ with P123-973 K > $Co_3O_4$-973 K>$Co_3O_4$/$Al_2O_3$-973 K > $Co_3O_4$/$Al_2O_3$ with P123-1473 K > $Al_2O_3$-973 K]. The existence of ${\gamma}$-alumina and the nature of the surface morphology are related to catalytic activity.

• Journal of the Korean Chemical Society
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• v.42 no.2
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• pp.214-219
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• 1998

Dynorphin B analogues, $[Arg^{11}, D-Ala^{12}]$dynorphin B, $[D-Ala^2, Ala^6, Arg^{11}, D-Ala^{12}]$dynorphin B, and dynorphin B (1-11) were synthesized by solid-phase method. A chloromethylated polystyrene resin cross-linked with 2% divinylbenzene was substituted with Thr in ethanol to contain 1.20 mmol Thr/g of resin. All amino groups of amino acids were protected with t-Boc group and 2,6-dichlorobenzyl and nitro groups were used to protect the side chains of Tyr and Arg, respectively. Stepwise synthetic method was applied for synthesis of the products. Dicyclohexylcarbodiimide (DCC) and 1-hydroxybenzotriazole (HOBT) were used as the coupling reagents. The crude peptides were purified by gel filteration on Sephadex LH-20 column $(2 \times 50 cm)$ using MeOH/MeCN (3/1) and then characterized with HPLC, amino acid analyzer.