• Analytical Science and Technology
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• v.18 no.6
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• pp.495-499
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• 2005

Notwithstanding antipathies against radiation, radiations are extensively used in various fields with development of the radiation technology. In order to safely manage such radiation it is necessary for development of the radiation measurement materials. In this paper a thin film type of plastic scintillator using in the contamination measurement devices was prepared. The plastic organic scintillator was prepared by simple solvent methods. It was possible to prepare in easy way and in various forms. The polysulfone which has high transparency and solubility was chosen. As the radiation measurement scintillator, the optical properties and radiation detection abilities were estimated.

• Elastomers and Composites
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• v.41 no.1
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• pp.49-56
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• 2006

The waste tire powder is modified with allylamine in the presence of ultraviolet radiation and the influence of surface modification on the thermal and rheological properties of polypropylene/waste tire powder composites was investigated. X-ray diffraction studies of PP/waste tire powder composite without compatibilizer, such as maleic anhydride-g-polypropylene (MA-PP), shows the increase in peak intensity of ${\beta}$ crystalline peaks, whereas it completely disappears in the presence of the MA-PP. Differential scanning calorimetry results further supported the above fact. The melt viscosities and storage modulus of the composites with modified waste tire powder show higher value than that of composites with unmodified powder and it is attributed to the interaction between amine group on modified powder surface and maleic anhydride of MA-PP.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.12 no.2
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• pp.68-72
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• 2002

The $\beta$-$FeSi_2$ and $\alpha$-$FeSi_2$ single crystals were synthesized by chemical vapour transport (CVT) using iodine as a transporting agent from the commercially available $FeSi_2$ powder. The $FeSi_2$ powder together with iodine were sealed in an evacuated quartz ampoule and the ampoule then being placed in two-zone electrical furnace for growing crystal. The CVT of $FeSi_2$ with iodine yielded $\beta$-$FeSi_2$ and $\alpha$-FeSi$_2$ single crystals at deposition temperature of 750 and $950^{\circ}C$ respectively. The source temperature was $1050^{\circ}C$ in both cases. The crystals of the $\alpha$-FeSi$_2$ phase were typically plate shaped with dimensions of about $10\times 10 \textrm{mm}^2$, whereas the crystals of orthorhombic $\beta$-$FeSi_2$ phase grew predominantly in the fonts of thin needle of about 10 mm in length. The composition of$\alpha$-FeSicrystal determined by electron probe microanalysis (EPMA) resulted in Si-rich $FeSi_{2.58}$ . 57. Furthermore, the CVT $\beta$-$FeSi_2$ crystal was found to be transformed to the high temperature $\alpha$-$FeSi_2$phase above $930^{\circ}C$.

• Korean Journal of Materials Research
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• v.21 no.2
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• pp.111-114
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• 2011

As a growth-template of ZnO nanorods (NR), a hexagonal $\beta-Ni(OH)_2$ nanosheet (NS) was synthesized with the low temperature hydrothermal process and its microstructure was investigated using a high resolution scanning electron microscope and transmission electron microscope. Zinc nitrate hexahydrate was hydrolyzed by hexamethylenetetramine with the same mole ratio and various temperatures, growth times and total concentrations. The optimum hydrothermal processing condition for the best crystallinity of hexagonal $\beta-Ni(OH)_2$ NS was determined to be with 3.5 mM at $95^{\circ}C$ for 2 h. The prepared $Ni(OH)_2$ NSs were two dimensionally arrayed on a substrate using an air-water interface tapping method, and the quality of the array was evaluated using an X-ray diffractometer. Because of the similarity of the lattice parameter of the (0001) plane between ZnO (wurzite a = 0.325 nm, c = 0.521 nm) and hexagonal $\beta-Ni(OH)_2$ (brucite a = 0.313 nm, c = 0.461 nm) on the synthesized hexagonal $\beta-Ni(OH)_2$ NS, ZnO NRs were successfully grown without seeds. At 35 mM of divalent Zn ion, the entire hexagonal $\beta-Ni(OH)_2$ NSs were covered with ZnO NRs, and this result implies the possibility that ZnO NR can be grown epitaxially on hexagonal $\beta-Ni(OH)_2$ NS by a soluble process. After the thermal annealing process, $\beta-Ni(OH)_2$ changed into NiO, which has the property of a p-type semiconductor, and then ZnO and NiO formed a p-n junction for a large area light emitting diode.

• KSBB Journal
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• v.22 no.5
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• pp.328-335
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• 2007

In this work ursolic acid (UA), a poorly water-soluble compound, was inclusion complexed with 2-hydroxypropyl-$\beta$-cyclodextrin (HP-$\beta$-CD) by various methods such as kneading, solvent evaporation and two types of supercritical fluid processes. The solubility and characteristics of these UA/HP-$\beta$-CD complexes were investigated by scanning electron microscopy, x-ray diffraction and HPLC. The water solubilities of the two complexes obtained from solvent evaporation and ASES processes were observed to increase up to 6$\sim$240 folds and 12$\sim$56 folds, respectively, compared with that of unprocessed UA. The stability of UA/HP-$\beta$-CD complex samples in cosmetic formulations was examined at various temperatures for one month. The UA/HP-$\beta$-CD complex prepared by solvent evaporation was found to be most stable among all the cosmetic formulations tested in our experiments.

• Journal of Radiation Protection and Research
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• v.24 no.1
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• pp.39-43
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• 1999

Thermoluminescent (TL) response characteristics of a thin LiF:Mg,Cu,Na,Si Teflon detectors have been studied for use in beta radiation detection. The detectors were fabricated from a mixture of LiF:Mg,Cu,Na,Si phosphor and Teflon powder which was molded into a thin disk form of $50mg/cm^2$ thickness. These detectors were irradiated to beta fields of $^{147}Pm,\;^{204}Tl\;and\;^{90}Sr/^{90}Y$ sources with a covering of Kapton foil ($2mg/cm^2$) and photon irradiation was carried out with a $^{137}Cs$ source at the Korea Atomic Energy Research Institute (KAERI). Batch uniformity was estimated to be 4.7% and the beta dose response presented linear relationship from 0.1 mGy to 100 Gy. The beta energy responses of thin detectors normalized to $^{137}Cs$ were presented as 0.46, 1.09 and 1.06 for $^{147}Pm,\;^{204}Tl\;and\;^{90}Sr/^{90}Y$ beta rays, respectively. The evaluated values for angular responses were $0.93{\pm}0.03\;(^{147}Pm),\;0.94{\pm}0.04\;(^{204}Tl),\;and\;0.92{\pm}0.05\;(^{90}Sr/^{90}Y)$. The results satisfied well a proposed ISO Standard for beta ray dosimeters.

• Progress in Medical Physics
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• v.2 no.2
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• pp.149-154
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• 1991

We have designed and applied the calibrationmethod of $\^$90/Sr Ophthalmic Applicaton by measuring the electron currents. We considered the number of electrons which is emitted from the source, the area of the source, and the electron stopping power in the water, and those data were used for calculation. Film was used for evaluating the accurate source area. Average electron stopping power was obtained by analyzing ${\beta}$-ray energy spectrum. We compared between the result from our method and that from the TLD measurements. The calibration result from our method shows 63.3 ${\pm}$5.1 cGy/sec, while 50.7${\pm}$7.3 cGy/sec from TLD measurement. But the supplier's specification tells 46.89.4cGy/sec.

• Journal of the Korean Society for Heat Treatment
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• v.10 no.4
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• pp.255-265
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• 1997

Precipitation and strengthening mechanisms in squeeze cast Mg-8.5wt%Li-4.5wt%Al have been investigated by differential scanning calorimetry(DSC), scanning electron microscopy(SEM), in-situ and ex-situ X-ray diffraction analysis and hardness measurement. Special emphasis was placed on the investigation of the precipitation behavior by the DSC technique. Microstructural and calorimetric analysis showed that ${\theta}$ and ${\delta}$ precipitates in the b.c.c. ${\beta}$ phase matrix, forming two exothermic peaks at the temperature ranges of $130^{\circ}C{\sim}180^{\circ}C$ and $236^{\circ}C{\sim}280^{\circ}C$. ${\theta}$ and ${\delta}$ dissolve into the matrix forming an endothermic peak at the temperature range of $280^{\circ}C{\sim}352^{\circ}C$. The as-cast microstructure consists of ${\alpha}$, ${\beta}$ and ${\delta}$. Peak strength was obtained after aging for 1 hour at $50^{\circ}C$. The aging time required for the peak strength decreased as the aging temperature increases. The hardness decrease during overaging was due to the coarsening of ${\theta}$ precipitates. Microhardness measurement showed that variation of the hardness of ${\beta}$ matrix was more pronounced than that of the ${\alpha}$ phase, indicating that the ${\beta}$ phase is more responsible for the strengthening of the Mg-8.5wt%Li-4.5wt%Al alloy.

• Restorative Dentistry and Endodontics
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• v.2 no.1
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• pp.20-26
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• 1976

Cellulose acetate electrophoresis was used for differential diagnosis of radicular cysts and granulomas. Sixteen periapical lesions were excised from sixteen teeth with radiographic evidence of periapical pathosis, and two normal periodontal tissues were surgically removed from two wisdom teeth. The tissue samples were separated into two parts. Half was prepared for cellulose acetate electrophoresis, and the electrophoretic patterns were scanned with Helena densitometer. The other half was examined histologically, and the histologic diagnoses were then compared with the electrophoretic patterns and with the x-ray findings. The results were the following: 1. The histopathologic results showed the presence of 13 granulomas (81.8%) and 3 cysts (18.3%). 2. An albumin pattern, alpha-globulin pattern, beta-globulin pattern, fibrinogen pattern and gamma-globulin pattern were found in all eighteen cases. 3. All eighteen cases were divided into normal periodontal tissue group, dental granuloma group, and radicular cyst group by the histopathologic diagnosis. The electrophoretic pattern of dental granuloma group and that of normal periodontal tissue group resembled each other. The two groups showed the highest percentage in beta-globulin fraction, and the beta-globulin of dental granuloma group(47.17%) was higher than that of normal periodontal tissue group (40.54%) by 6.63%. On the contrary, beta-globulin fraction of radicular cyst group (28.00%) was much lower than those of the granuloma group (47.17%) and normal periodontal tissue group (40.54%), and alpha-globulin of radicular cyst group (34.16%) was much higher than those of the granuloma group (20.04%) and normal group (19.58%). 4. Five cases (31.3%) of the sixteen periodontal lesions showed different results between histopathologic diagnoses and radiographic findings.

• Journal of the Korean Chemical Society
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• v.38 no.8
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• pp.608-615
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• 1994

The isolation, purification and characterization of a carotenoprotein from the carapace of Pnaeus orientalis were investigated. The carotenoprotein was purple with broad λmax between 480, 409, 318 and 280 nm. Apparent structures were estimated by using X-ray diffractometry and scanning electron microscope, respectively. The molecular weight of the carotenoprotein complex had been determined by GPC and PAGE. The heavier complex, designated the $\alpha$-form (M.W = 170 KDa), was dissociated to a major subunit, $\beta$-form (M.W = 42 KDa). SDS-PAGE of $\alpha$-form showed apparently oligomeric pattern, and also $\beta$-form gave two polypeptides corresponding to 22 KDa and 19 KDa, respectively. The amino acid of the two proteins $({\alpha}-and\;{\beta})$-form, lipid and free fatty acid compositions were described. The prosthetic groups of the carotenoprotein were confirmed by TLC, IR, $^1H$-NMR, MS and various organic reactions as astaxanthin, astaxanthin monoester and astaxnathin diester.