• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.30 no.6
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• pp.488-496
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• 2004

Oral & Maxillofacial surgery can lead to complications that result in abnormal sensation or movement. Inferior alveolar nerve(IAN) injury can result in dysesthesia, paresthsia of the lower lip and chin, so patients presenting with IAN damage suffer from sensory loss. But diagnosis of the nerve injury is largely limited to the subjective statements made by the patient. Distribution of sympathetic nerves parallels the distribution of the somatosensory nerves. Loss of sensory tone causes a concomitant loss of sympathetic activity, resulting in vasodilation of the cutaneous blood vessels that demonstrates greater heat loss. Digital infrared thermographic imaging(DITI) detects infra-red radiation given off by body. DITI can detect minute difference in temperature from different parts of the body and translates the amount of heat into quantitative data. The area of different temperature correlated with pain or disease can be visualized by corresponding color. The objective of this study was to determine the efficacy of DITI in objectively assessing IAN injury. The 19 normal subjects and the 14 patients underwent DITI scan. The normal subjects received unilateral IAN block anesthesia with 2 ml of 2% lidocaine (IAN bolck group) to evaluate temporary alteration in nerve function. Patient group were patients with unilateral IAN damage (dysesthesia or paresthesia) after surgical treatment(Mn. 3rd molar Extraction, etc.). The surgical procedure performed within 6 months of test. The results were as follows. 1. No significant differences in temperature were found between left and right sides of the lower lip and chin in the control group. 2. Significant temperature differences were found between the anesthetized and non-anesthetized sides of the lower lip and chin in the IAN block group. 3. Significant temperature differences were found between the involved and uninvolved sides of the lower lip and chin areas of the experimental group. The results of the study show that DITI can be an useful and effective means of objectively assessing and visualizing IAN damage.

• Journal of the Korean Society of Safety
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• v.25 no.3
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• pp.53-60
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• 2010

LPG(Liquefied Petroleum Gas) vehicles in metropolitan area are being applied to improve air quality and have been proven effective for the reduction of air pollutant. In addition, LPG demand is growing rapidly as an environmentally friendly energy source and its gas station is also increasing every year. Consequently, this study tries to find out the influence of flame caused by the VCE(Vapor Cloud Explosion) in filling station on the adjacent combustibles and people by simulating relevant quantity of TNT. In addition, the damage estimation was conducted by using API regulations. If the scale of the radiation heat is known by calculating the distance of flame influence from the explosion site, the damage from the site can be easily estimated. And the accident damage was estimated by applying the influence on the adjacent structures and people into the PROBIT model. According to the probit analyze, the spot which is 30m away from the flame has 100% of the damage probability by the first-degree burn, 99.2% of the damage probability by the second-degree burn and 93.4% of the death probability by the fire.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.6 s.324
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• pp.93-99
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• 2004

According to rapid increment of demand for wireless Local Area Network (LAN), the HyperLAN of 5.1-533GHz and 5.725-5.825GHz is newly allocated for wireless LAM in many regions over the world. Also, because most of mobile communication equipments are small, the size of antenna is important factor of effective design. In this paper, the compacted and wide bandwidth antenna is designed for wireless LAN at 5GHz band. Although the structure of U-shaped slot antenna is simple, It has large bandwidth of $10-40\%$. Also, the U-slot antenna has good radiation pattern. However, in general, the size of U-slot antenna is large. Therefore, it is difficult to apply to wireless equipment such as PDA and Notebook. This proposed antenna has a wide bandwidth by U-shaped slot in rectangular patch and is compacted by using two layered dielectric substrates and foam. For the design of U-slot antenna, the Finite Difference Time Domain method is applied. Also, the method of MPI parallel program is used for the enhancement of the analyzing speed of the FDTD method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.12A
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• pp.1233-1241
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• 2008

We design, fabricate, and measure a MIMO antenna system mountable on a small PCB (such as UMPC). The proposed antenna system accommodates three radiation elements on the PCB area of $40mm\;{\times}\;100mm$. Two of them employ a slot type and one uses a modified monopole with an inverted L shape expecting high isolation and polarization purity. The bandwidth of each proposed MIMO antenna ranges from 80MHz and 200MHz at the center frequency of 1.8 GHz. The isolations between ports have been found to be greater than 10dB over the interested frequency band. Besides, the proposed MIMO system has been evaluated in terms of ARC(Active Reflection Coefficient, TARC(Total ARC), correlation, MEG, and etc. The envelope correlation is calculated to be much less than 0.04 and the ratio of the mean effective gain(MEG) between the antennas is found to be close to unity.

• Journal of Ginseng Research
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• v.41 no.3
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• pp.290-297
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• 2017

Background: The use of X-ray phase-contrast microtomography for the investigation of Chinese medicinal materials is advantageous for its nondestructive, in situ, and three-dimensional quantitative imaging properties. Methods: The X-ray phase-contrast microtomography quantitative imaging method was used to investigate the microstructure of ginseng, and the phase-retrieval method is also employed to process the experimental data. Four different ginseng samples were collected and investigated; these were classified according to their species, production area, and sample growth pattern. Results: The quantitative internal characteristic microstructures of ginseng were extracted successfully. The size and position distributions of the calcium oxalate cluster crystals (COCCs), important secondary metabolites that accumulate in ginseng, are revealed by the three-dimensional quantitative imaging method. The volume and amount of the COCCs in different species of the ginseng are obtained by a quantitative analysis of the three-dimensional microstructures, which shows obvious difference among the four species of ginseng. Conclusion: This study is the first to provide evidence of the distribution characteristics of COCCs to identify four types of ginseng, with regard to species authentication and age identification, by X-ray phase-contrast microtomography quantitative imaging. This method is also expected to reveal important relationships between COCCs and the occurrence of the effective medicinal components of ginseng.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.12
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• pp.545-552
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• 2003

When a Si PIN diode is exposed to fast neutrons, it results in displacement damage to the Si lattice structure of the diode. Defects induced from structural dislocation become effective recombination centers for carriers which pass through the base of a PIN diode. Hence, increasing the resistivity of the diode decreases the current for the applied forward voltage. This paper involves the development of a neutron sensor based on the phenomena of the displacement effect damaged by neutron exposure. The neutron effect on the semiconductor was analyzed. Several PIN diode arrays with various thickness and cross-section area of the intrinsic layer(I layer) were fabricated. Under irradiation tests with a neutron beam, the manufactured diodes have a good linearity to neutron dose and show that the increase of thickness of I layer and the decrease of cross-section of PIN diodes improve the sensitivity. Newly developed PIN diodes with thicker I layer and various cross section, were retested and then showed the best neutron sensitivity at the condition that the I layer thickness was similar to a side length. On the basis of two test results, final discrete PIN diodes with a rectangular shape were manufactured and the characteristics as neutron detectors were analyzed through the neutron beam test using on-line electronic dosimetry system. Developed PIN diode shows a good linearity as dosimetry in the range of 0 to 1,000cGy(Tissue) and its neutron sensitivity is 13mV/cGy at constant current of 5mA, that is three times higher than that of commercially available neutron detectors. And the device shows little dependency on the orientation of the neutron beam and a considerable stability in annealing test for a long period.

• Nuclear Engineering and Technology
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• v.55 no.6
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• pp.2158-2165
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• 2023

Marine radioactivity monitoring is critical for taking immediate action in case of unexpected nuclear accidents at nuclear facilities located near coastal areas. Especially when the level of contamination is not predictable, mobile monitoring systems will be useful for wide-area ocean radiation survey and for determination of the level of radioactivity. Here, we used a silicon photomultiplier and a high-efficiency GAGG crystal to fabricate a compact, battery-powered gamma spectroscopy that can be used in an ocean environment. The developed spectroscopy has compact dimensions of 6.5 × 6.5× 8 cm³ and weighs 560 g. We used LoRa, a low-power wireless protocol for communication. Successful data transmission was achieved within 1.4 m water depth. The developed gamma spectroscopy was able to detect radioactivity from a ¹³⁷Cs point source (3.7 kBq) at a distance of 20 cm in water. Moreover, we demonstrated an unmanned radioactivity monitoring system in a real sea by combining unmanned surface vehicle with the developed gamma spectroscopy. A hidden ¹³⁷Cs source (3.07 MBq) was detected by the unmanned system at a distance of 3 m. After successfully testing the developed mobile spectroscopy in an ocean environment, we believe that our proposed system will be an effective solution for mobile real-time marine radioactivity monitoring.

• Journal of Chest Surgery
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• v.30 no.12
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• pp.1237-1241
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• 1997

Tracheal stenosis is a difficult disease entity to manage. Laser ablation is one effective treatment for treacheal stenosis and can be utilized if tracheal reconstructive surgery is impossible. Potassium titanyl phosphate laser, transmitted via flexible quartz fiber, can be precisely manipulated through flexible bronchoscope under local anesthesia. We treated 7 patients with trach al and broncheal lesion under local anesthesia with KTP laser from January 1995 to July 1996. The patients included three males and four females. The age of patients ranged from 22 to 66 years with a mean of 43.7 years The etiology of tracheal stenosis in patients was stenosis after tracheostomy(3 cases), prolong inturbation in cases of sepsis(1 cases), and the recurrence of lung cancer within endobronchial lesion(2 cases). In the cases of tracheal stenosis treated with laser ablation, there were 2 cases of recurrence of stenosis at the anastomosis site after the operation, 3 cases of stenosis at tracheostomy site, and 2 cases of local recurrence of lung cancer. The site of the tracheal stenosis was the balloon site of the tracheostomy tube(3-4cm inferior to the tracheostomy site, 2-3cm superior to the carina) and the anastomosis site that were narrowed to less than 5mm(4 cases). For the stenosis lesion in the endobronchial area, there were 2 patients with a lesion at the anterior wa l, 1 patient with a lesion at the posterior wall, 2 patients with circumferential stenosis. Laser ablation time was 25.4 $\pm$5.9min and used energy was 1768 $\pm$365J. We have used KTP laser via (lexible bronchoscope without major complications. Adjuvant radiation therapy may prevent fibroblast proliferation which leads to restenosis. In three patients of restenosis after laser ablation, adjuvant irradiation started within 4 hours after laser ablation, and the radiation doses were 1500cGy given in five fraction. In patients with adjuvant radiation therapy, stenosis has not recurred

• Radiation Oncology Journal
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• v.24 no.3
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• pp.157-163
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• 2006

[ $\underline{Purpose}$ ]: To evaluate the role of postoperative adjuvant chemoradiotherapy in rectal cancer, we retrospectively analyzed the treatment outcome of patients with rectal cancer taken curative surgical resection and postoperative adjuvant chemoradiotherapy. $\underline{Materials\;and\;Methods}$: A total 46 patients with AJCC stage II and III carcinoma of rectum were treated with curative surgical resection and postoperative adjuvant chemoradiotherapy. T3 and T4 stage were 38 and 8 patients, respectively. N0, N1, and N2 stage were 12, 16, 18 patients, respectively. Forty patients received bolus infusions of 5-fluorouracil ($500\;mg/m^2/day$) with leucovorin ($20\;mg/m^2/day$), every 4 weeks interval for 6 cycles. Oral Uracil/Tegafur on a daily basis for $6{\sim}12$ months was given in 6 patients. Radiotherapy with 45 Gy was delivered to the surgical bed and regional pelvic lymph node area, followed by $5.4{\sim}9\;Gy$ boost to the surgical bed. The follow up period ranged from 8 to 75 months with a median 35 months. $\underline{Results}$: Treatment failure occurred in 17 patients (37%). Locoregional failure occurred in 4 patients (8.7%) and distant failure in 16 patients (34.8%). There was no local failure only. Five year actuarial overall survival (OS) was 51.5% and relapse free survival (RFS) was 58.7%. The OS and RFS were 100%, 100% in stage N0 patients, 53.7%, 47.6% in N1 patients, and 0%, 41.2% in N2 patients (p=0.012, p=0.009). The RFS was 55%, 78.5%, and 31.2% in upper, middle, and lower rectal cancer patients, respectively (p=0.006). Multivariate analysis showed that N stage (p=0.012) was significant prognostic factor for OS and that N stage (p=0.001) and location of tumor (p=0.006) were for RFS. Bowel complications requiring surgery occurred in 3 patients. $\underline{Conclusion}$: Postoperative adjuvant chemoradiotherapy was an effective modality for locoregional control of rectal cancer. But further investigations for reducing the distant failure rate are necessary because distant failure rate is still high.

• Journal of the Korean Geotechnical Society
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• v.33 no.11
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• pp.21-34
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• 2017

The ground penetrating radar (GPR) signal can be measured with different amplitudes according to the directivity, so the directivity of the antenna should be considered. The objective of this study is to investigate the directivity of antenna by analyzing the reflection characteristics of electromagnetic waves radiated from the antenna, and to evaluate effective range of angle that can inspect an abnormal area according to the directivity of antenna. For the measurement of the directivity, a circular metal bar is used as reflector and the signals are measured by changing the angle and the distance between reflector and antenna in the E- and H-plane. The boundary distance between the near field and the far field is determined by analyzing the amplitudes of reflected signals, and two points with different distances from each of near and far fields are designated to analyze radiation patterns in near and far fields. As a result of radiation pattern measurement, in the near field, minor lobes are observed at angle section at more than $50^{\circ}$ in both E- and H-plane. Therefore, antenna has the directivity for the direction of main lobe and minor lobes in near field. In the far field, antenna has the directivity for a single direction of main lobe because minor lobes are not observed. The amplitude of the signal reflected from the near field is unstable, but it can be distinguished from noise. Therefore, in the near field, the ground anomaly can be detected with high reliability. On the other hand, the amplitude of the signal reflected from the far field is stable, but it is hard to distinguish between reflected signal and noise because of the excessive loss of electromagnetic wave. The analyses of directivity in the near and the far fields performed in this study may be effectively used to improve the reliability of the analyses of abnormal area.