• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.05a
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• pp.383-386
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• 2007

In this study, the analysis was carried out for Electrical Discharge Machining (EDM) characteristics of the Cu electrodes by LIGA process. The shape of electrodes has 324 pins for the cavity of BGA(Ball Grid Array) type test socket mold. BGA test sockets are used in the inspection process of the semi-conductor I.C chip manufacturing. In the work, the machining performance for EDM of the electrodes was analyzed on dimensional accuracy and wear rate. The dimensional accuracy was measured for dimension of the pins, pitch size between the pins and the roundness of corner edge using optical measuring machine.

• Design & Manufacturing
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• v.2 no.5
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• pp.30-33
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• 2008

Injection Molding is the most effective process for mass production of plastic parts. The injection molding process is composed with several steps such as Filling, Packing, Holding, Cooling, Ejecting. Among them, filling and packing process should be considered carefully to improve accuracy of dimension, surface quality of plastic parts. Usually the quality above-mentioned is managed with weight of part after molding on the field. In this paper, a series of experiment for molding automotive front bumper was conducted with cavitity temperature sensor to optimize switch-over time(V-P switching), hot runner vale gate sequence time during filling and packing step for the purpose of uniform quality, weight at every molding. As a result, it was found that it is effective method to use temperature sensor in injection molding for quality control of plastic molding.

• Journal of Veterinary Clinics
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• v.17 no.1
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• pp.289-292
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• 2000

A Holstein cattle with third pregnancy was found to have clinical emergency findings of anxiety, dyspnea and recumbency at just before parturition. So Cesarean section and observation of internal organs were taken. Macroscopic examination showed enlargement of th lymph nodes and spleen, and ascites. A large tumor mass with solid and white to gray-white and focal hemorrhage, 55$\times$120cm in dimension and weighing 25.5kg was found in pelivc cavity. For conventional light microscopy, tissue samples were fixed in 10% neutral formalin solution, and then paraffin embedding, sectining and H-E staining were performed. In microscopic findings, tumor tissue, lymph node and spleeen were composed of mainly lymphoid tumor cells and the number of white blood cells in peripheral blood were increased 10-fold more than in normal. We concluded this tumor was bovine lymphoma.

• Journal of Chest Surgery
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• v.18 no.3
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• pp.482-486
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• 1985

Pulmonary sequestration is an uncommon congenital malformation characterized by the presence of non-functioning lung tissues which receives its blood supply from an anomalous systemic artery instead of a pulmonary arterial branch. We present a case of intralobar pulmonary sequestration experienced lately. The patient was 7 years old girl with the complaints of chronic productive cough and right lower chest pain. Serial chest films showed a large cyst with or without a air-fluid level on the right lower lung field. Aortography revealed an aberrant artery originating from thoracic aorta just above the diaphragm and that drained into the right inferior pulmonary vein. During operation, a large abscess cavity measuring 6.5x5x5 cm in dimension at the right lower lobe was noted. And the two aberrant arteries, measuring 3 mm in diameter, arising from thoracic aorta 5 cm above the diaphragm was noted. After division and ligation of the aberrant arteries, right lower lobectomy was performed and the patient`s postoperative course was uneventful.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.05a
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• pp.368-371
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• 2005

In this paper, a small band pass filter is designed using new probe type for wireless communication system. In order to provide a band pass filter which can be reduced in dimension, can be reduced in height, and can be surface-mounted. The filter was fabricated using $TE_{01{\delta}}$ mode dielectric resonator. The input/output probes are attached to coner portion of the rectangular metal cavity. Results of the manufactured filter$(12{\times}12{\times}8mm)$ show that the center frequency is 9.953GHz, the insertion loss is -2.98 dB, the 3dB-bandwidth is 15 MHz, and the lode Q is 663.

• 한국초전도학회:학술대회논문집
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• v.10
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• pp.21-21
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• 2000

The Josephson Plasma resonance in single crystalling Bi2Sr2CaCu2O8 has been investigated at a microwave frequency of 35 GHz in a cavity resonator. A sharp resonance is observed in a perpendicular oscillating magnetic field. The former is independent of the sample dimension, shile the latter shift to higher field as the sample size L is reduced, and it disappears when L becomes smaller than the critical length. The longitudinal plasma mode is a Nambu-Goldston mode in a superconductor, the experimental distinction between the longitudinal and the transverse mode leads to the conclusion that the existence of the Nambu-Goldston mod as predicted by Anderson was experimentally confirmed by direct observation of the Josephson plasma resonance with longitudinal excitations. The finite gap found in Josephson plasma resonance also provides a direct proof of the Anderson-Higgs mechanism within the context of the spontaneously broken phase symmetry of the Gauge-field theory in a superconductor.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.75-80
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• 2012

Helmholtz resonator is widely used acoustic instrument which has high absorption characteristics at its resonance frequency. Particularly it maintains good performance even in the low frequency region that is difficult to control by general porous absorptive materials. However, under severely high sound pressure level, the absorption characteristics are changed by increase of resistance due to nonlinear behavior of neck impedance. Because of this nonlinear behavior, it is difficult to obtain the expected absorption performance under high sound pressure environment. Thus, in order to prevent excessive rise of resistance, the resonator with neck having cross section dimension decrease away from the entry of the resonator cavity could be suggested. This paper introduces the experiment method and results about nonlinear characteristics of Helmholtz resonator with tapered neck and proposes the approximate nonlinear impedance model.

• The korean journal of orthodontics
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• v.24 no.2
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• pp.319-329
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• 1994

This study was carried out to research the adaptation patterns of head posture after activator therapy in functional class III malocclusion patients. For this purpose, 29 functional class III malocclusion patients, from the ages of 8 to 13 years old, were used. 1, Increse in capacity of oral cavity capacity were found in all the samples, but craniocervical angulation were varied into incresed group and decreased group after activator therapy. 2. Head posture exhibited the compensatory adaptation in the relative growth increments of the vertical dimension, ALFH and PLFH. 1) A group with more PLFH and less sagittal angle showed relatively small growth increment in PLFH during the treatment period, thus craniocervical angulation was increased. 2) A group with less PLFH and more sagittal angle showed relatively great growth incrmenet in PLFH during the treatment period, thus craniocervical angulation was decreased.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.2
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• pp.96-103
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• 2011

Rotor grip is used as a component of rotor system in unmanned helicopter. Instead of usual machining, hot forging process has been considered to improve its proof stress against repeated loading conditions and crash in the farm-field. Die design and forming analysis have been performed according to the conditions such as billet volume, flash, cavity filling, and the distribution of damage during the forming by using FE analysis. In the results of analysis, the possibility of structural failure in the model has not been found because its maximum effective stress is much lower than yield strength of the titanium alloy. In the forging die design, flash has been allowed because of low production in the industrial field. Preform design was studied by using FE-analysis, and its optimal dimension was obtained in the hot forging of rotor grip with titanium alloy.

• Journal of Chest Surgery
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• v.14 no.4
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• pp.354-358
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• 1981

Intralobar pulmonary sequestration is a rare congenital malformation characterized by a cystic portion of the lung that derives its arterial blood supply through aberrant vessel directly of systemic circulation. Intralobar pulmonary sequestration Is usually contained within the visceral pleura of a pulmonary lobe and its venous drainage to the pulmonary venous system. We experienced a case of pulmonary sequestration preoperatively confirmed. The patient was 17 year old female whose complaints were mild fever and profuse purulent sputum. Chest film showed a large thin walled cystic lesion with air-fluid level at the left lower posterior basal lung field. Aortogram revealed an aberrant artery originated from thoracic aorta just above the diaphragm and that drained via pulmonary vein into the left atrium. At time of operation, a large abscess cavity measuring 9x8x3 cm in dimension at the left lower lobe was noted. And the aberrant artery, measuring 0.5 cm in diameter and 2 cm in length, arising from thoracic aorta just above the diaphragm was noted. After division and ligation of the aberrant artery, a left lower lobectomy was performed and the patient`s postoperative course was uneventful.