• Korean Journal of Head & Neck Oncology
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• v.14 no.1
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• pp.81-87
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• 1998

Fine needle aspiration cytology was used widely to select thyroid nodules for surgery. The result could be highly reliable for most malignancies and for benign nodules. The purpose of this study was to determine the value of frozen biopsy by directly comparing the results of preoperative fine needle aspiration cytology to frozen biopsy examination. In our university hospital, 103 patients with thyroid nodule were operated during the years 1996 through 1997. A comparison of accuracy of the fine needle aspiration cytology with frozen biopsy was made for 85 patients who underwent both procedures. The 85 patients were separated into two groups. The group I included 65 patients, whose preoperative fine needle aspiration cytology results were reported as benign or malignant lesion definitely. The group II included 85 patients, the patients whose reported fine needle aspiration cytologic result was suspicious for malignancy were regarded .as malignant lesion and results for follicular neoplasm were regarded as benign lesion. The accuracy of both procedures was compared on two group also. The sensitivity, specificity, and accuracy of frozen biopsy were 76.7%, 93.5%, and 85.2% in group I and 75.6%, 95.5%, and 85.9% in group II, respectively, compared with 63.3%, 87.1%, and 75.4% in group I and 65.4%, 81.8%, and 72.9% in group II for fine needle aspiration cytology. On benign lesion, the accuracy was 95.5% in frozen biopsy and 68.2% in fine needle aspiration cytology, 75.6% in frozen biopsy and 53.7% in fine needle aspiration cytology on malignant lesion. We conclude that although fine needle aspiration cytology is the reliable diagnostic test in the evaluation of thyroid nodule, frozen biopsy should be performed intraoperatively, because fine needle aspiration cytology is insufficiently sensitive for reliable surgical planning.

• Applied Chemistry for Engineering
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• v.28 no.6
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• pp.679-684
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• 2017

Hydrated liquid crystalline vesicles incorporating a edge activator, which confers flexibility to the vesicle membranes, were prepared and niacinamide was encapsulated in them. The formation of liquid crystalline phases and their thermal phase transitions were investigated by polarized optical microscopy and differential scanning calorimetry (DSC), respectively. Droplet sizes of the vesicles were reduced to several tens of nanometers by incorporating edge activators, such as sodium deoxycholate, lysolecithin, or polysorbate 80. The amount of niacinamide permeated into a pig skin increased greatly using the hydrated liquid crystalline vesicles compared to the case where niacinamide was applied in an aqueous solution state. The vesicles incorporating 10% sodium deoxycholate increased the amount of niacinamide permeated nearly four times. These results suggest that edge activators are effective in improving the skin permeability of vesicles.

• Applied Microscopy
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• v.38 no.3
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• pp.185-193
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• 2008

An experimental comparison of the detection properties between imaging plate and film for recording the electron diffraction pattern was carried out on a radiation-sensitive material, an aluminum trihydroxide(gibbsite, ${\gamma}-Al(OH)_3$), through the electron beam irradiation. Because the imaging plate has a wide dynamic range sufficient for recording extremely low- and high-electron intensities, the range of spatial frequency for the diffraction pattern acquired by the imaging plate was extended to two times larger than the range by the film, especially at a low electron dose condition(${\leq}0.1\;e^-/{\mu}m^2$). It is also demonstrated that the imaging plate showed better resolving power for discriminating fine intensity levels even in saturated transmitted beam. Hence, in the respect of investigating the structures of radiation-sensitive materials and cryo-biological specimens, our experimental demonstrations suggest that the imaging plate technique may be a good choice for those studies, which have to use an extremely low electron intensity for recording.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.12 no.3
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• pp.126-132
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• 2002

The nanocrystalline zirconia powder with anisotropic shapes was synthesized by hydrothermal treatment of the tetragonal zirconia prepared by aging the zirconium hydroxide precipitate, which was obtained from the reaction between $ZrOCl_2{\cdot}8H_2O$ and KOH solutions under the fixed pH of 13.5, at $100^{\circ}C$ for 24 h. With increasing the hydrothermal reaction temperature and time, the fraction of tetragonal phase with spherical zirconia decreased, whereas, relatively the fraction of monoclinic phase with spindle-like and rod shape zirconia increased. As increased concentration of the NaOH solution it promoted the particle size to become larger and the crystalline phase to transform tetragonal to monoclinic. However, the specific surface area at the early stage of the reaction increased and subsequently decreased because of grain growth in powder with longer reaction time.

• Journal of the Korean Ceramic Society
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• v.40 no.12
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• pp.1213-1219
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• 2003

Porous ceramics for microoganism carriers were prepared with amorphous alumina and pore formers by hydrothermal reaction, burn-out and wash-out method. Activated carbon with average size of 67,222, and 405 $\mu\textrm{m}$, organic polymer and inorganic salt were used as pore formers. Specimens were hydrothermally treated at 200$^{\circ}C$ for 24 h, heat-treated at 650$^{\circ}C$ for 5 h, and washed out at 80$^{\circ}C$ for 48 h. The formation of crystalline phase, porosity, pore size distribution and compressive strength were measured. The specimen with activated carbon was transformed to boehmite phase, but organic polymer and inorganic salt inhibited the aquohydroxoy complex gel and crystalline formation. The porous ceramics for microoganism carriers using activated carbon as a pore formers was successfully prepared, which is composed of ${\gamma}$-alumina phase with porosity of above 70 vol% and the compressive strength of 40 kgf/$\textrm{cm}^2$.

• Journal of the Korean Geotechnical Society
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• v.19 no.4
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• pp.83-93
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• 2003

This research, in order to study the effects of initial shear stress of anisotropically consolidated sand that has 0.558% fines, performed several undrained static and dynamic triaxial test. To simulate the real field conditions, loose and dense samples were prepared. Besides, the cyclic shear strength of Nakdong River sand under various combinations of initial static shear stress, stress path, pore water pressure and residual strength relationship was studied. By using Bolton's theory, peak internal friction angle at failure which has considerable effects on the relative density and mean effective stress was determined. In p'- q diagram, the phase transformation line moves closer to the failure line as the specimen's initial anistropical consolidation stress increases. Loose sands were more affected than dense sands. The increase of consolidation stress ratio from 1.4 to 1.8 had an effect on liquefaction resistance strength resulting from the increase of relativity density, and showed similar CSR values in dense specimen condition.

• Journal of the Korean Geotechnical Society
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• v.20 no.6
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• pp.137-150
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• 2004

Aging effect of sands showed insignificant result in comparison with that of clay, so that it has not been studied so far. But, as penetration resistance increase has been observed with the lapse of time after deposition and disturbance, aging effect of sands has been actively investigated by field tests, and recently many researchers are performing not oかy field tests but also laboratory tests on sands, so aging effects of sands have been also examined by laboratory tests. In this study, to observe the aging effect of undrained static shear behavior for Nak-Dong River sand, undrained static triaxial tests were performed with changing relative density$(D_r)$, consolidation stress ratio$(K_c)$, and consolidation time. These tests showed that modulus within elastic section increased as consolidation time increased, and in addition, phase transformation point strength$(S_{PT})$ and critical stress ratio point strength $(S_{CSR})$ also increased. But pore water pressure ratio$(u/{p_c}')$ decreased as consolidation time increased, so with this various result, aging effect of static shear for sands can be observed as well.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.5
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• pp.18-28
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• 2009

To analyze influences under faults caused by a stator winding short and to evaluate an effectiveness of a diagnostic algorithm a faulty model for an inverter-driven permanent magnet synchronous motor is presented. Even though the conventional dq motor model obtained through the transformation of phase voltage model is widely used to analyze and control the motor, it can not be used in the analysis of a faulty motor since the 3-phase balanced condition is no longer hold under the fault caused by a stator winding short, and thus, it is very difficult to obtain motor input voltages from the pole voltage of an inverter. To overcome this problem, a faulty model for an inverter-driven permanent magnet synchronous motor is proposed by considering the line voltage of 3-phase variables. The effectiveness of the proposed faulty model is verified through comparative simulations and experiments using DSP TMS320F28335 and motor built to allow a partial short of inter-turn.

• Fashion & Textile Research Journal
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• v.16 no.2
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• pp.326-332
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• 2014

To develop cool touch feeling fabrics for summer clothing material, it was manufactured several compositions of woven fabrics, having rayon multi-filament yarn (non-twisted) as warp and various kinds of yarn, such as viscose rayon multi-filament yarn (twisted), tencel$^{(R)}$ spun yarn, PET high absorbance quick dry filament yarn, and PET based rayon-like yarn, as weft. After preparing the fabrics, basic properties of the fabrics were investigated, such as air-permeability, tensile strength, absorption rate, drying rate, etc. Also, surface warm / cool sensations of the woven fabrics were assessed by Qmax Warm / Cool Touch Tester. It was observed that the fabrics composed of viscose rayon multi-filament yarn (warp) and PET high absorbance quick dry filament yarn (weft) showed excellent surface cool touch sensation-the highest Qmax value. This is because the fabric having flat shaped PET high absorbance quick dry filament shows the largest contact area with Qmax measuring plate. And, the fabric also showed superior high absorbance and quick dry property as expected. In addition, we treated phase change material (PCM) on the surface of the fabric composed of viscose rayon multi-filament yarn (warp) and PET high absorbance quick dry filament yarn(weft) to improve the cool touch feeling. However, the surface cool touch feeling was impaired by resin treated with PCM during the finishing process.

• Korean Journal of Materials Research
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• v.23 no.6
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• pp.329-333
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• 2013

The structural phase transformations of $0.7Pb(Mg_{1/3}Nb_{2/3})O_3-0.3PbTiO_3$ (PMN-0.3PT) were studied using high resolution x-ray diffraction (HRXRD) as a function of temperature and electric field. A phase transformational sequence of cubic (C)${\rightarrow}$tetragonal (T)${\rightarrow}$rhombohedral (R) phase was observed in zero-field-cooled conditions; and a $C{\rightarrow}T{\rightarrow}$monoclinic $(M_C){\rightarrow}$ monoclinic ($M_A$) phase was observed in the field-cooled conditions. The transformation of T to $M_A$ phase was realized through an intermediate $M_C$ phase. The results also represent conclusive and direct evidence of a $M_C$ to $M_A$ phase transformation in field-cooled conditions. Beginning from the zero-field-cooled condition, a $R{\rightarrow}M_A{\rightarrow}M_C{\rightarrow}T$ phase transformational sequence was found with an increasing electric field at a fixed temperature. Upon removal of the field, the $M_A$ phase was stable at room temperature. With increasing the field, the transformation temperature from T to $M_C$ and from $M_C$ to $M_A$ phase decreased, and the phase stability ranges of both T and $M_C$ phases increased. Upon removal of the field, the phase transformation from R to $M_A$ phase was irreversible, but from $M_A$ to $M_C$ was reversible, which means that $M_A$ is the dominant phase under the electric field. In the M phase region, the results confirmed that lattice parameters and tilt angles were weakly temperature dependent over the range of investigated temperatures.