• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.32 no.2
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• pp.161-167
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• 2006

Objectives: Pericoronitis was the most common indication for mandibular third molar surgery and there are no universally acceptable predictive criteria for pericoronitis occurrence. This study was designed to analyze the correlation of the pericoronitis and the eruption state of the mandibular third molar using panoramic radiographs statistically. Materials and Methods: 218 patients whose chief complaint was the extraction of the mandibular third molar were examined. The presence and absence of pericoronitis, age, sex, position of extraction site, angulation, impaction degree, position to the anterior border of mandibular ramus, distance between distal cementoenamel junction of second molar and mesial cementoenamel junction of the mandibular third molar were assessed. Then the correlation of pericoronitis and the eruption state of the mandibular third molar were analyzed by Student's t-test and chi-square test. Results: There was no correlation between Pericoronitis and age, sex, position of the mandibular third molar. The angulation(P=0.005), impaction degree(P=0.043), relation with anterior border of mandibular ramus(P=0.003), distance between distal cementoenamel junction of second molar and mesial cementoenamel junction of the mandibular third molar(P<0.05) were correlated with pericoronitis. Conclusions: The occurrence of the pericoronitis can be predicted by the eruption state of the mandibular third molar such as angulation, impaction degree, relation with anterior border of mandibular ramus, distance between distal cementoenamel junction of second molar and mesial cementoenamel junction of third molar.

• Journal of the Korean Ceramic Society
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• v.42 no.10 s.281
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• pp.660-664
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• 2005

Hydroxyapatite powder was injected into the tooth after decayed tooth clinic. The microstructure of tooth was observed after a tooth extraction in the body. The hydroxyapatite powder was stiffened and the junction of hydroxyapatite powder and tooth was observed. The Ca/P atomic ratio of hydroxyapatite-tooth boundary was higher than hydroxyapatite matrix. And microhardness of hydroxyapatite matrix was 92.4 Hv. The junction of hydroxyapatite powder and tooth was due to the $Ca^{2+}$ ion shift of hydroxyapatite or the firm waxy body was due to setting of hydroxyapatite powder.

• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.2921-2923
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• 2005

This paper presents to generate 3D building model using estimation of rooftop surface after 3D line segment extraction using hybrid stereo matching techniques in terms of the co-operation of area-based stereo and feature-based stereo. we first performed a junction extraction from 3D line segment data which was obtained by stereo images, and finally generated building's reliable rooftop surface model using LSE(Least Square Error) method after creating surfaces by grouped and fixed junction points. we generated synthetic images for experimentation by photo-realistic simulation on Avenches data set of Ascona aerial images.

• Journal of the Semiconductor & Display Technology
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• v.2 no.2
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• pp.17-20
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• 2003

The current drive in an MOSFET is limited by the intrinsic channel resistance. All the other parasitic elements in a device structure playa significant role and degrade the device performance. These other resistances need to be less than 10%-20% of the channel resistance. To achieve the requirements, we should investigate a methodology of separation and quantification of those resistances. In this paper, we developed the extraction method of resistances using calibrated TCAD simulation. The resistance of the extension region is also partially determined by the formation of a surface accumulation region that forms under the gate in the tail region of the extension profile.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.4
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• pp.367-372
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• 2004

Two new extraction methods for the thermal Resistance of HBT(Heterojunction Bipolar Transistors) are proposed. First, the analytical expression, based on the thermal characteristics that the base to emitter junction voltage drops with the increase of junction temperature, is derived. Second, the thermal resistance equation that can predict the measured DC(Direct Current) data optimally is derived. These optimal thermal resistance expression is applied to the 2 finger 2${\times}$20${\mu}{\textrm}{m}$-AlGaAs/GaAs HBT and shows the good agreement with the measured data.

• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.763-766
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• 2003

A direct parameter extraction method using several two-port parameter equations derived in cutoff and active bias modes has been studied to obtain an accurate Gummel-Poon BJT model. First, dc model parameters were extracted from slopes and y-axis intercepts of I-V curve and Gummel plot. The pad capacitances and junction capacitance parameters were determined by using measured S-parameter sets in the cutoff bias. The resistance and transit time parameters were extracted by using measured S-parameter sets in the active bias.

• Journal of Physiology & Pathology in Korean Medicine
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• v.32 no.2
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• pp.106-112
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• 2018

The aim of this research was to determine the diverse effects of Sappan Lignum extract and brazilin on human keratinocyte HaCaT cells. We confirmed the antioxidant effect of Sappan Lignum extract and brazilin was analyzed by using an ABTS assay, confirming the efficacy of water extraction method. Also, we examined effect of Sappan Lignum extract and brazilin on the cell viability, using the MTS assay in HaCaT cells. mRNA expression levels of tight junction-related genes associated with skin barrier in HaCaT cells were analyzed using quantitative real-time PCR analysis. Sappan Lignum extract increased the cellular activity of HaCaT cells and the expression of the tight junction-related genes claudin 3, claudin 6, and ZO-2. Brazilin displayed the same effects as that of the extract on HaCaT cells activity and tight junction-related genes expression. Furthermore, dispase assay demonstrated altered cell-cell adhesion strength of Sappan Lignum extract or brazilin treated HaCaT cells. Sappan Lignum extract or brazilin might be an useful ingredient in skin-mosturizinng and anti-wrinkle cosmetics, given its effects of altering mRNA expression of tight junction-related genes and enhancing cell-cell adhesion strength of HaCaT cells.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.10
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• pp.25-34
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• 2002

In this paper, silicidation induced Schottky contact area was obtained using the current voltage(I-V) characteristics of shallow cobalt silicided p+-n and n+-p junctions. In reverse bias region, Poole-Frenkel barrier lowering influenced predominantly the reverse leakage current, masking thereby the effect of Schottky contact formation. However, Schottky contact was conclusively shown to be the root cause of the modified I-V behavior of n+-p junction in the forward bias region. The increase of leakage current in silicided n+-p diodes is consistent with the formation of Schottky contact via cobalt slicide penetrating into the p-substrate or near to the junction area and generating trap sites. The increase of reverse leakage current is proven to be attributed to the penetration of silicide into depletion region in case of the perimeter intensive n+-p junction. In case of the area intensive n+-p junction, the silicide penetrated near to the depletion region. There is no formation of Schottky contact in case of the p+-n junction where no increase in the leakage current is monitored. The Schottky contact amounting to less than 0.01% of the total junction was extracted by simultaneous characterization of forward and reverse characteristics of silicided n+-p diode.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.7
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• pp.7-12
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• 2004

An improved extraction method considering ac current crowding effect is investigated to determine intrinsic ( $C_{\mu}$) and extrinsic ( $C_{\mu}$) base-collector capacitances of bipolar junction transistors separately. The drawbacks of conventional methods are pointed out, and the improved extraction equations are derived from a cutoff mode equivalent circuit with the ac crowding capacitance. The frequency response curves of modeled current and power gains using the extracted values of $C_{\mu}$ and $C_{\mu}$ have much better agreements with measured ones than those of the conventional methods, verifying the accuracy of the improved technique.

• Journal of Korean Neurosurgical Society
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• v.38 no.1
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• pp.12-15
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• 2005

Objective : Cerebral edema develops in the brain tumors by loosening of the endothelial tight junction. Tight junction[TJ] proteins, such as occludin and claudin bind adjacent cells tightly. Authors examine the expression rate of occludin in human brain tumors to evaluate the effect of altered expression of occludin on cerebral edema. Methods : Seventy surgical specimens stored at $-70^{\circ}C$ were used. It included 14 astrocytic tumors, 27 meningiomas, 12 scwannomas, 7 pituitary adenomas, 6 hemangioblastomas. and 4 craniopharyngiomas. After protein extraction, expression of occludin was investigated by Western blot analysis. The tumors were classified according to World Health Organization[WHO] classification. Results : The expression rates of occludin in brain tumors were : glioma [8/14=57.1%]. meningioma [16/27=59.3%], schwannoma [10/12=83.3%], pituitary adenoma [6/7=85.7%], hemangioblastoma [6/6=100%], and craniopharyngioma [3/4=75.0%]. The expression rate in glioma and meningioma was lower than other brain tumors. In gliomas, high grade tumor [1/4=25.0%] exhibited lower expression rate of occludin than low grade one [7/10=70.0%]. Conclusion : These results suggest that the expression of occludin is different among the various kinds of brain tumors. In gliomas, its expression is correlated with the histological grade. It may indicate that occludin plays a role in the development of edema in the brain tumors.