• Textile Coloration and Finishing
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• v.31 no.3
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• pp.147-154
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• 2019

In this study, poly(ethylene terephthalate)(PET) fibres dyed with Disperse Red 167 using supercritical $CO_2$ technology. The purpose of this study was to investigate relationship between PET fibers and supercritical $CO_2$ during dyeing. The effects of temperature, pressure, dyeing time and mass ratio between the dye and PET in the dyeing chamber were considered. Thermal and mechanical properties of the fibers were investigated. Tensile strength of dyed PET fibers decreased at higher temperature and pressure conditions. DSC and DMA results indicated that the Tg and Tm values decreased significantly when compared to the pure PET fibers. However, uniformly dyed PET fibers were typically observed.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.310-315
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• 2008

Authors design a rotary-type small-scaled linear induction motor(LIM) and a performance test machine before manufacturing a real-scaled LIM for a railway transit. The designed LIM is a single-sided, short primary type and its primary has 4 poles. The rated power is 10(kW). In order to analyze characteristics of the LIM, authors use a mixed 2D-3D FEM analysis. 3-D FEM analysis is used for calculating a distribution of eddy-current on the semi-caped AL-sheet of the secondary reaction. Authors calculate a correction factor of conductivity and an equivalent conductivity on the secondary AL-sheet using a normalized eddy-current. The equivalent conductivity which is calculated in this way includes a transverse edge-effect of the LIM. Authors apply the equivalent conductivity on the secondary AL-sheet of 2D-FEM model and get performance characteristics of the LIM. Basic characteristics such as thrust and normal force, input current, efficiency and power factor of the LIM have been analyzed with the variation of frequency and speed. In order to apply an air-gap control system, the variation of the basic characteristics have been analyzed with the air-gap length variation of the LIM. Finally, authors introduce an operation mode using the air-gap control system and conduct a research on feasibility of the system.

• YAKHAK HOEJI
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• v.38 no.5
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• pp.520-524
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• 1994

A number of 7-[(3-methylthio or methylthiomethyl)-3-pyrrolinyl] quinolone-3-carboxylic acids were synthesised by condensation of 7-fluoro substituted quinolone-3-carboxylic acid with 3-methylthio-3-pyrroline or 3-methylthiomethyl-3-pyrroline. The in vitro antimicrobial activity of them were tested against twenty species of Gram-positive or Gram-negative microorganisms. It showed remarkable antibacterial activity, particularly against Gram-positive microoganisms. Among those 1-cyclopropyl-6,8-difluoro-7-[(3-methylthiomethyl) -3-pyrrolinyl]-1,4-dihydro-4-oxo-3-quinolinecarboxylic acid(12a) and 1-cycl opropyl-6-fluoro-8-chlore-7-[(3-methylthiomethyl)-3-pyrrolinly]-1,4-dihydro-4-oxo-3-quinolinecarboxylic acid(12b) showed the most potent in vitro antibacterial activity.

• Archives of Craniofacial Surgery
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• v.19 no.4
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• pp.287-290
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• 2018

Tumoral calcinosis is a condition characterized by deposition of calcium salts in the skin and subcutaneous tissue, commonly found around the joints. However, tumoral calcinosis of the auricle is extremely rare. We present the case of a 13-year-old boy with tumoral calcinosis of the helix of the ear auricle. A 13-year-old boy presented with a 10-year history of an enlarging mass on the left auricle. The mass was hard, non-tender, and non-compressible. The patient had no history of trauma. Complete surgical excision and pathological examination of the specimen was performed. The final diagnosis of the excised mass was tumoral calcinosis. After 9 months of follow-up, there were no signs of recurrence of the tumor and the patient was satisfied with the surgical results. Tumoral calcinosis of the auricle is extremely rare and may be misdiagnosed as other tumors. Pathological examination is essential for definitive diagnosis and complete surgical excision should be considered as the treatment of choice.

• Archives of Craniofacial Surgery
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• v.20 no.1
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• pp.62-65
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• 2019

Odontoma is an asymptomatic slow-growing odontogenic tumor. It is usually found by chance in the maxilla or mandible on radiography, or when it deforms the adjacent teeth. It is commonly found in patients who are 30 years of age or younger. We report our encounter with an odontoma within a dentigerous cyst found incidentally in a 56-year-old man. He presented with abnormal fullness in the right infraorbital area of the cheek. During the evaluation of the mass, we incidentally detected the odontogenic tumor within a dentigerous cyst in the patient's maxilla. Under general anesthesia, complete surgical drainage of the infraorbital cystic mass was performed. Enucleation of the odontogenic tumor and a bone grafting from the iliac bone were also performed. The final diagnosis was odontoma. After 2 years of follow-up, there was no sign of recurrence of the tumor. In case of odontogenic tumors, even in old patients, it is important to suspect an odontoma. When odontoma accompanies a dentigerous cyst, surgical excisional biopsy should be performed to rule out malignancy. In case of a large bony defect after enucleation, autogenous bone grafting is essential for reconstruction.

• Archives of Craniofacial Surgery
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• v.21 no.6
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• pp.368-371
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• 2020

Schwannoma, also known as neurilemmoma, is a tumor of the nerve sheath, which most often occurs in the peripheral nerves of the extremities. Schwannoma can be accompanied by symptoms such as pain, paresthesia, and Tinel sign; however, patients can also be asymptomatic. Here, we present the case of a 17-year-old woman who presented with a slowly growing, asymptomatic, postauricular mass that appeared 10 years prior. Ultrasonography was performed, and the mass was thought to be an epidermal inclusion cyst. However, the clinical manifestation during surgery was not correlated to an epidermal inclusion cyst, leading to the suspicion of schwannoma from the posterior branch of the great auricular nerve. After a meticulous dissection, schwannoma was diagnosed based on a permanent section biopsy. Postoperative complications and recurrence were not observed. Schwannoma in the peripheral nerve area of the face is rare. Therefore, an investigation of tumors that occur where the nerve passes using imaging and clinical features is necessary to confirm the diagnosis of schwannoma and to establish suitable treatment methods.

• Journal of Microbiology and Biotechnology
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• v.31 no.2
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• pp.189-196
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• 2021

Periplanetasin-2 from cockroach exhibits broad-spectrum antimicrobial activity. The underlying antibacterial mechanisms rely on the stimulation of reactive oxygen species overproduction to induce apoptotic cell death. A promising strategy to increase the bioavailability of periplanetasin-2 involves reducing the dose through combination therapy with other antibacterials that show synergistic effects. Thus, the synergistic antibacterial activity of periplanetasin-2 with conventional antibacterial agents and its mechanisms was examined against Escherichia coli in this study. Among the agents tested, the combinations of periplanetasin-2 with vancomycin and chloramphenicol exhibited synergistic effects. Periplanetasin-2 in combination with vancomycin and chloramphenicol demonstrated antibacterial activity through the intracellular oxidative stress response. The combination with vancomycin resulted in the enhancement of bacterial apoptosis-like death, whereas the combination with chloramphenicol enhanced oxidative stress damage. These synergistic interactions of periplanetasin-2 can help broaden the spectrum of conventional antibiotics. The combination of antimicrobial peptides and conventional antibiotics is proposed as a novel perspective on treatments to combat severe bacterial infection.

• Textile Coloration and Finishing
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• v.34 no.3
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• pp.197-206
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• 2022

The purpose of this study was to confirm the optimal spinning conditions for PLA (Polylactic acid) as a fiber forming polymer. According to the melt spinning test results of PLA, the optimal spinning temperature was 258℃. However, it needs to note that relatively high pack pressure was required for spinning at 258℃. At an elevated temperature, 262℃, mono filament was broken easily due to hydrolysis of PLA at a higher temperature. In case of fiber strength, it was confirmed that the draw ratios of 2.7 to 3.3 were optimal for maximum strength of melt spun PLA. Above the draw ratio, 3.3, the strength of the PLA fibers was lowered. It was presumed that cleavage of the PLA polymer chain over maximum elongation. The heat setting temperature of GR (Godet roller) showed that the maximum strength of the PLA fibers was revealed around 100℃. The degree of crystallinity and the strength of the PLA fibers were decreased above 100℃. The optimal take-up speed (Spinning speed) was around 4,000m/min. Thermal analysis of PLA showed 170℃ and 57℃ as Tm (melting temperature) and Tg (glass transition temperature), respectively.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.7
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• pp.15-24
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• 2021

In this paper, to analyze the types of surface morphology error according to factors that cause machining error, the experiments were conducted in the ultra-precision diamond machine using a diamond tool. The factors causing machining error were classified into the pressure variation of compressed air, external shock, tool errors, machining conditions (rotational speed and feed rate), tool wear, and vibration. The pressure variation of compressed air causes a form accuracy error with waviness. An external shock causes a ring-shaped surface defect. The installed diamond tool for machining often has height error, feed-direction position error, and radius size error. The types of form accuracy error according to the tool's errors were analyzed by CAD simulation. The surface roughness is dependent on the tool radius, rotational speed, and feed rate. It was confirmed that the surface roughness was significantly affected by tool wear and vibration, and the surface roughness of Rz 0.0105 ㎛ was achieved.

• Journal of Veterinary Clinics
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• v.38 no.2
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• pp.85-88
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• 2021

A 9-year-old, intact female Shih-tzu dog presented with a three-week history of anorexia, lethargy, and weight loss. Abdominal radiography revealed a mass in the right cranial quadrant of the abdomen that was displacing the right kidney caudally. Ultrasonography showed a large, irregular, heterogeneous hepatic mass and a small amount of peritoneal fluid. On computed tomography (CT), a large hypoattenuating mass with heterogeneous contrast enhancement occupied the right lateral lobe, and parts of the right medial and caudate lobes of the liver. There was no evidence of regional lymph node or pulmonary metastasis. Lobectomy of the right medial, right lateral and caudate liver lobes was performed, however, the patient did not recover from surgery. Hepatoblastoma was confirmed by histological examination. Hepatoblastoma is rare in dogs, and this is the first report describing CT imaging of hepatoblastoma in a dog.