• Archives of Plastic Surgery
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• v.41 no.2
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• pp.148-152
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• 2014

Background Free flap surgery for head and neck defects has gained popularity as an advanced microvascular surgical technique. The aims of this study are first, to determine whether the known risk factors such as comorbidity, tobacco use, obesity, and radiation increase the complications of a free flap transfer, and second, to identify the incidence of complications in a radial forearm free flap and an anterolateral thigh perforator flap. Methods We reviewed the medical records of patients with head and neck cancer who underwent reconstruction with free flap between May 1994 and May 2012 at our department of plastic and reconstructive surgery. Results The patients included 36 men and 6 women, with a mean age of 59.38 years. The most common primary tumor site was the tongue (38%). The most commonly used free flap was the radial forearm free flap (57%), followed by the anterolateral thigh perforator free flap (22%). There was no occurrence of free flap failure. In this study, risk factors of the patients did not increase the occurrence of complications. In addition, no statistically significant differences in complications were observed between the radial forearm free flap and anterolateral thigh perforator free flap. Conclusions We could conclude that the risk factors of the patient did not increase the complications of a free flap transfer. Therefore, the risk factors of patients are no longer a negative factor for a free flap transfer.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.3
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• pp.328-334
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• 2012

This paper proposes a design technique of wide-band antenna for handy phone with 700 MHz LTE(Long Term Evolution) low frequency bandwidth. The proposed antenna based on the PIFA(Planar Inverted-F type Antenna) structure was designed and considered. In order to realize the wide bandwidth, a round structure which is able to control the electric path length of current and a branch line element which can be obtain the dual resonance characteristics were introduced in this design. As a result, It was realized about 95 MHz bandwidth in spite of very small space of $30{\times}34mm$ used for FR-4 substrate with relative permitivity of 4.4 at 700 MHz band. Measurement results of return loss, bandwidth and gain radiation pattern were agreed well with their calculation results.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.6
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• pp.3743-3746
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• 2013

Background: Of patients with non small cell lung cancer (NSCLC), around one third are locally advanced at the time of diagnosis. Because only a proprotion of stage III patients can be cured by surgery, in order to improve the outcomes, sequential or concurrent chemoradiation, or concurrent chemoradiation with induction or consolidation is offered to the patients with locally advanced NSCLC. Today, PET combined with computerized tomography (PET-CT) is accepted as the most sensitive technique for detecting mediastinal lymph node and extracranial metastases from NSCLC. We aimed to compare PET-CT and conventional staging procedures for decisions regarding curative treatment of locally advanced NSCLC. Materials and Methods: A total of 168 consecutive patients were included from Acibadem Kayseri Hospital, Acibadem Adana Hospital and Kayseri Research and Training Hospital in this study. Results: While the median PFS was $13.0{\pm}1.9$ months in the PET-CT group, it was only $6.0{\pm}0.9$ in the others (p<0.001). The median OS values were $20.5{\pm}15.6$ and $11.5{\pm}1.5$ months, respectively (p<0.001). Discussion: As a result, we found that staging with PET CT has better results in terms of survival staging. This superiority leads to survival advantage in patients with locally advanced NSCLC.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.2
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• pp.212-216
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• 1999

SiC(3C) photodiodes (PDs) were fabricated on p-type Si(111) substrates using chemical vapor deposition (CVD) technique by pyrolyzing tetramethylsilane (TMS) with $H_{2}$ carrier gas. Electrical properties of SiC(3C) were investigated by Hall measurement and current-voltage (I-V) characteristics. SiC(3C) layers exhibited n-type conductivity. Ohmic contact was formed by thermal evaporation Al metal through a shadow-mask. The optical gain $(G_{op})$ of the SiC(3C)/Si PD was measured as a function of the incident wavelength. For the analysis of the photovoltaic detection of the Sic(3C) n/p PD, the spectral response (SR) has calculated by using the electrical parameters of the SiC(3C) layer and the geometric structure of the PD. The peak response calculated for properly chosen parameters was about 0.75 near 550 nm. We expect a good photoresponse in the SiC(3C) heterostructure for the wavelength range of 400~600 nm. The SiC(3C) photodiode can detect blue and near ultraviolet (UV) radiation.

• The Journal of the Korea Contents Association
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• v.15 no.7
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• pp.282-288
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• 2015

A monte carlo simulation about shielding material and thickness of the syringe shield for radiation shield was performed. As a result of analysis, high atomic number materials such as tungsten, lead and bismuth have the highest shielding effect. However, $^{18}F$, $^{67}Ga$ and $^{111}In$ show high energy distribution in the region with thin shielding thickness. As the thickness of shielding materials increased, the energy distribution decreased due to reduction of ${\gamma}$-ray. In the case of low atomic number materials, they, showed energy distribution from highest to lowest, were barium sulfate, steel, stainless, iron and copper. Aluminum, plastic, concrete and water showed diverse aspect. they showed relatively high energy distribution because of increased ${\gamma}$-ray that penetrate the shield.

• Journal of the Optical Society of Korea
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• v.19 no.4
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• pp.327-333
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• 2015

This paper reports the fabrication of various micro-lensed single-mode optical fibers through the use of an enhanced peak power $CO_2$ laser beam. The end faces of the optical fibers are exposed to the $CO_2$ laser beam to form convex, concave, and conical shape optical fiber tips. Peak power of the $CO_2$ laser beam was varied from 0.8 W to 1.5 W depending on the shape of the optical fiber tip. We also discover the dependence of the angle of the optical fiber tip on the rotation angle and the number of $CO_2$ laser irradiations. The angle shows an increasing trend with both these parameters. We achieve a wide range of lenticular fibers with end face angle varying from $4.47^{\circ}$ to $8.13^{\circ}$. Furthermore, we investigate the emission pattern of light from the developed micro-lensed fibers. The proposed $CO_2$ laser based optical fiber reshaping technique shows great consistency, and thus is suitable for commercial applications.

• Publications of The Korean Astronomical Society
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• v.15 no.spc2
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• pp.21-25
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• 2000

The ionosphere, the atmosphere of the earth ionized by solar radiations, has been strongly varied with solar activity. The ionosphere varies with the solar cycle, the seasons, the latitudes and during any given day. Radio wave propagation through or in the ionosphere is affected by ionospheric condition so that one needs to consider its effects on operating communication systems normally. For examples, sporadic E may form at any time. It occurs at altitudes between 90 to 140 km (in the E region), and may be spread over a large area or be confined to a small region. Sometimes the sporadic E layer works as a mirror so that the communication signal does not reach the receiver. And radiation from the Sun during large solar flares causes increased ionization in the D region which results in greater absorption of HF radio waves. This phenomenon is called short wave fade-outs. If the flare is large enough, the whole of the HF spectrum can be rendered unusable for a period of time. Due to events on the Sun, sometimes the Earth's magnetic field becomes disturbed. The geomagnetic field and the ionosphere are linked in complex ways and a disturbance in the geomagnetic field can often cause a disturbance in the F region of the ionosphere. An enhancement will not usually concern the HF communicator, but the depression may cause frequencies normally used for communication to be too high with the result that the wave penetrates the ionosphere. Ionospheric storms can occur throughout the solar cycle and are related to coronal mass ejections (CMEs) and coronal holes on the Sun. Except the above mentioned phenomena, there are a lot of things to affect the radio communication. Nowadays, radio technique for probing the terrestrial ionosphere has a tendency to use satellite system such as GPS. To get more accurate information about the variation of the ionospheric electron density, a TEC measurement system is necessary so RRL will operate the system in the near future.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.21 no.6
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• pp.246-252
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• 2011

The semiconducting $MnSi_{1.73}$ compound has been recognized as a thermoelectric material with excellent oxidation resistance and stable characteristics at elevated temperature. In the present work, we applied mechanical alloying (MA) technique to produce $MnSi_{1.73}$ compound using a mixture of elemental manganese and silicon powders. The mechanical alloying was carried out using a Fritsch P-5 planetary mill under Ar gas atmosphere. The MA powders were characterized by the X-ray diffraction with Cu-$K{\alpha}$ radiation, thermal analysis and scanning electron microscopy. Due to the observed larger loss of Si relative to Mn during mechanical alloying of $MnSi_{1.73}$, the starting composition of a mixture Mn-Si was modified to $MnSi_{1.83}$ and then $MnSi_{1.88}$. The single $MnSi_{1.73}$ phase has been obtained by mechanical alloying of $MnSi_{1.88}$ mixture powders for 200 hours. It is also found that the grain size of $MnSi_{1.73}$ compound powders analyzed by Hall plot method is reduced to 40 nm after 200 hours of milling.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.35 no.4
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• pp.248-255
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• 2013

Reconstruction techniques of orofacial defects caused by wide excision of the intraoral malignant lesions are various. Although radial forearm free flap is a common donor site on reconstruction of soft tissue defect, anterolateral thigh (ALT) free flap also has an established site in orofacial soft tissue reconstruction as the favored donor flap with recent progress of the microsurgical technique. A 59-year-old female complained of hyperplastic mass on the right retromolar and buccal cheek, which was diagnosed as a squamous cell carcinoma (SCC) by an incisional biopsy. Before the operation, we planned a wide excision of the SCC lesion, supraomohyoid neck dissection, reconstruction with radial forearm free flap (RFFF), and split thickness skin graft. We accidentally found an arterial variation of the forearm area during elevation of RFFF, and changed the plan of reconstruction operation to reconstruction with ALT free flap. Operative sites was healed well during the post-operative period, and we referred to the department of radiation oncology for post-operative radiotherapy.

• Imaging Science in Dentistry
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• v.49 no.4
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• pp.265-272
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• 2019

Purpose: To compare the diagnostic accuracy of cone-beam computed tomography (CBCT) with that of parallel(PPA) and oblique projected periapical(OPA) radiography for the detection of different types of peri-implant bone defects. Materials and Methods: Forty implants inserted into bovine rib blocks were used. Thirty had standardized bone defects(10 each of angular, fenestration, and dehiscence defects), and 10 were defect-free controls. CBCT, PPA, and OPA images of the samples were acquired. The images were evaluated twice by each of 2 blinded observers regarding the presence or absence and the type of the defects. The area under the receiver operating characteristic curve (AUC), sensitivity, and specificity were determined for each radiographic technique. The 3 modalities were compared using the Fisher exact and chi-square tests, with P<0.05 considered as statistical significance. Results: High inter-examiner reliability was observed for the 3 techniques. Angular defects were detected with high sensitivity and specificity by all 3 modalities. CBCT and OPA showed similar AUC and sensitivity in the detection of fenestration defects. In the identification of dehiscence defects, CBCT showed the highest sensitivity, followed by OPA and PPA, respectively. CBCT and OPA had a significantly greater ability than PPA to detect fenestration and dehiscence defects(P<0.05). Conclusion: The application of OPA radiography in addition to routine PPA imaging as a radiographic follow-up method for dental implantation greatly enhances the visualization of fenestration and dehiscence defects. CBCT properly depicted all defect types studied, but it involves a relatively high dose of radiation and cost.