• Transactions of Materials Processing
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• v.24 no.1
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• pp.20-27
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• 2015

Hot tensile tests were conducted at different temperatures ranging from $20^{\circ}C$ to $550^{\circ}C$ to evaluate the mechanical properties of Al5052 seamless tubes. Such tubes can provide the technological foundation for complex forming using hot air bulging. Hot air bulging is one of the recently developed hydroforming techniques and it has some limitations in terms of cycle times. The benefits of hot air bulging are weight and cost savings through part consolidation and reduced post-forming processes such as welding and piercing. In order to extend the forming limits of Al lightweight material hot air bulging was investigated. A heated tube was placed in a heated die and sealed at the ends by sealing cylinders. The heated tube was subsequently expanded against the die cavity wall by internal pressure using air medium. The results of the current study show that axial feeding speed and air pressure have an effect on the formability of Al tubes during air bulging at elevated temperatures.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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• pp.145-147
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• 2009

The benefits of hydroforming technology are known as weight and cost savings through part consolidation and reduced post-forming processes such as welding and piercing. Hydroforming technology has some weaknesses in terms of process cycle times. But, as the hydraulic system and process designs are continuously developed, the cycle time is also reduced to acceptable and competitive levels. Hot air bulging is one of recently developed hydroforming techniques. Hot air bulging in order to further extend the forming degrees of Al lightweight material is investigated. A heated tube is placed in a heated die and sealed at the ends by sealing cylinders. The tube is subsequently expanded against the die cavity wall by internal pressure provided by air medium. The result of this study shows that axial feeding speed and air pressure have an effect on formability of Al air bulging at elevated temperature.

• Tuberculosis and Respiratory Diseases
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• v.57 no.4
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• pp.381-385
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• 2004

Pulmonary gangrene is a rare and severe complication of bacterial pneumonia, where a pulmonary segment or lobe is sloughed due to parenchymal devitalization of the parenchyma, with secondary anaerobic infection and necrosis caused by pulmonary vascular thrombosis. Prior to the antibiotic era, massive pulmonary gangrene was potentially fatal. Herein, a case of pulmonary gangrene in a 67-year-old man is reported. He complained of fever, chills, dyspnea and purulent sputum of 5 days duration. The plain chest radiograph showed well-marginated right upper lobe consolidation, with bulging minor fissure, suggestive of a Klebsiella infection. A contrast CT scan demonstrated consolidation of the right upper lobe, with a central necrotizing portion. Klebsiella species was confirmed from both sputum and blood cultures. After appropriate antibiotics, the chest X-ray and CT scan 3 weeks later showed a large cavity with an air-fluid level, sloughing-off and extrusion of necrotic lung tissue, suggestive of pulmonary gangrene. Seven months later, the right gangrenous lung showed severe volume loss on a chest radiograph. The management of pulmonary gangrene has been somewhat controversial. Herein, it was managed without surgical drainage or resection. If the antibiotic therapy had failed, then a surgical approach would have been considered.

• Nuclear Engineering and Technology
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• v.52 no.2
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• pp.417-428
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• 2020

Investigations of the commercial aircraft impact effect on nuclear island infrastructures have been drawing extensive attention, and this paper aims to perform the safety assessment of Generation III nuclear power plant (NPP) buildings subjected to typical commercial aircrafts crash. At present Part III, the local damage of the rigid components of aircraft, e.g., engine and landing gear, impacting the steel concrete (SC) structures of NPP containment is mainly discussed. Two typical SC target panels with the thicknesses of 40 mm and 100 mm, as well as the steel cylindrical projectile with a mass of 2.15 kg and a diameter of 80 mm are fabricated. By using a large-caliber air gas gun, both the projectile penetration and perforation test are conducted, in which the striking velocities were ranged from 96 m/s to 157 m/s. The bulging velocity and the maximal deflection of rear steel plate, as well as penetration depth of projectile are derived, and the local deformation and failure modes of SC panels are assessed experimentally. Then, the commercial finite element program LS-DYNA is utilized to perform the numerical simulations, by comparisons with the experimental and simulated projectile impact process and SC panel damage, the numerical algorithm, constitutive models and the corresponding parameters are verified. The present work can provide helpful references for the evaluation of the local impact resistance of NPP buildings against the aircraft engine.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1982.05a
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• pp.14.2-15
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• 1982

Serous otitis media (SOM) is one of the most common otologic diseases which was first discribed by Politzer in 1869. Currentely, among many methods introduced to treat SOM, ventilation tube insertion is considered to be the most popular and standard method being used. However due to complication of it, there remains many disputable various problems. In order to review the clinical aspect of SOM and search for the effects and safety of ventilation tube, we studied 97 SOM patients, who had performed V-tube from Jan. 1981 to Feb. 1982 at ENT dept. of Severance Hospital. Analizing the clinical symptoms, age distribution, associated disease, otoscopic findings of ear drum, degree of hearing loss, hearing gain after insertion of V-tube and complications, following results were obtained. 1) As a subjective symptom, among 29 cases all patients had hearing loss, 19 cases (65.6%) had tinnitus, 12 cases (44.4%) had autophony and 10 cases (34.5%) of the patients had sensation of ear fullness. 2) In age distribution, 6 to 10 year old group was most numerous up to 42 cases (43.3%) and 20 years and over was 23 cases (23.5%) 3) In adult group SOM tend to be involved unilaterally whereas young child group had tendency involving bilaterally. 4) 49 cases (50.05%) were associated with tonsillitis and adenoid vegetation, 15 cases (15.5%) were associated with sinusitis, 4 cases (4.1%) had nasal allergy. 5) In preoperative otoscopic findings, 62 ears (47.7%) had retraction, 37 ears (23.6%) had bulging, 34 ears (21.7%) had color change, and 29 ears (19.7%) had no significant findings. 6) In characteristics of middle ear fluid, child group was tend to have mucinous content (84.2%) while adult group had serous content (62.5%). 7) Average preoperative air-bone gap of pure tone was 25.3 dB. 8) 24 ears (72.7%) had over 10 dB of postoperative hearing gain and average hearing gain was 17.2 dB. 9) There were 44 ears (28.1%) of complications. Among them 37 ears (23.6%) had infection, 3 ears had atelectasis, 2 ears had granulation tissue, 2 ears had permanent perforations. 10) Among 37 ears suffered from post-op. infection, 19 ears (51.4%) had initial infection just after insertion of ventilation tube, 18 ears (48.6%) were infected during the course of post-ventilation tube. Of 37 infected ears, 26 ears (70.3%) responded to conservative care, while 11 ears (29.7%) was cured after removal of ventilation tube.