• 천문학회보
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• 제35권1호
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• pp.26.2-26.2
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• 2010

It has been a puzzle in solar physics how a low-lying magnetic structure such as a solar prominence surrounded by a strongly line-tied overlying field sometimes intrudes through the latter and goes into eruption. A numerical simulation study of the solar coronal plasma reveals that a ballooning instability can explain this type of eruptive process. We consider an idealized situation with two flux ropes merging. When magnetic field lines from different flux ropes reconnect, a new field line connecting farther footpoints is generated. Since the field line length abruptly increases, the field line expands outward. If the plasma beta is low, this expansion takes place more or less evenly over the whole field line. If, on the other hand, the plasma beta is high enough somewhere in this field line, the outward expansion is not even, but is localized as in a bulging balloon. This ballooning section of the magnetic field penetrates out of the overlying field, and eventually the originally underlying field and the overlying field come to interchange their apex positions. This process may explain how a field structure that has stably been confined by an overlying field can occasionally show a localized eruptive behavior.

• Nuclear Engineering and Technology
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• 제54권1호
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• pp.138-151
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• 2022

Cladding ballooning and rupture are the important phenomena at the early stage of a severe accident. Most severe accident analysis codes determine the cladding rupture based on simple parameter models. In this paper, a FRTMB module was developed using the thermal-mechanical model to analyze the fuel mechanical behavior. The purpose is to judge the cladding rupture with the severe accident analysis code. The FRTMB module was integrated into the self-developed severe accident analysis code ISAA to simulate the PHEBUS FPT3 experiment. The predicted rupture time and temperature of the cladding were basically consistent with the measured values, which verified the correctness and effectiveness of the FRTMB module. The results showed that the rising of gas pressure in the fuel rod and high temperature led to cladding ballooning. Consequently, the cladding hoop strain exceeded the strain limit, and the cladding burst. The developed FRTMB module can be applied not only to rod-type fuel, but also to plate-type fuel and other types of reactor fuel rods. Moreover, the FRTMB module can improve the channel blockage model of ISAA code and make contributions to analyzing the effect of clad ballooning on transient and subsequent parts of core degradation.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2002년도 춘계공동학술발표회요약집
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• pp.163.1-163
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• 2002

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 1994년도 한국우주과학회보 제3권2호
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• pp.50-50
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• 1994

No Abstract. See Full-text

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2005년도 춘계학술발표회
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• pp.601-602
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• 2005

• 대한두개안면성형외과학회지
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• 제10권2호
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• pp.86-90
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• 2009

Purpose: Inferior blow-out fracture is the common facial fracture. Unsatisfactory functional and aesthetic outcomes are frequent when it is treated inappropriately. If fractures are extended and reach the posterior end of orbital floor, enophthalmos frequently followed as complication. The purpose of this study was to evaluate reduction technique of extensive inferior blow-out fracture with ballooning of foley catheter through endoscopic transnasal approach and implantation of $Medpor^{(R)}$ through subciliary approach. Methods: A retrospective study was performed on 14 patients with extensive inferior blow-out fracture who underwent ballooning of foley catheter through endoscopic transnasal approach with implantation of $Medpor^{(R)}$ through subciliary approach. Patients were operated from May 2005 to November 2007. Data for 14 patients were acquired from patient's charts. Preoperative and postoperative data for enophthalmos, diplopia, limitation of extraocular motion were reviewed. Preoperative and postoperative CT scan were also checked. The patients were followed up from 4 to 18 months. Results: The enophthalmos was corrected in all patients. Among 7 patients with diplopia preoperatively, diplopia was resolved in three patients postoperatively. The diplopia persisted in four patients and two of them also had limitation of extraocular motion postoperatively. The limitation of extraocular motion occurred in seven patients preoperatively. But five patients recovered after operation immediately. These symptoms were resolved about three months after the operation. Conclusion: The ballooning of foley catheter through endoscopic transnasal approach with implantation of $Medpor^{(R)}$ through subciliary approach can be considered one of the appropriate technique for extensive inferior blowout fracture.

• 비파괴검사학회지
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• 제33권2호
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• pp.212-218
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• 2013

A transfer method of neutron radiography was developed to measure the size of the end plug and a gap of an intact K102L-2, the irradiated fuel of a ballooned K174L-3, a ballooned and ruptured K98L-3. A typical irradiation time of 25 min. was determined to obtain a film density of between 2 and 3 of SR X-ray film with neutrons of $1.5{\times}10^{11}n{\cdot}cm^{-2}$. To validate and calibrate the results, a RISO fuel standard sample, Cd plate and ASTM-BPI/SI were used. An activated latent image formed in the $100{\mu}m$ Dy foil was subsequently transferred in a dark room for more than 8 hours to the SR film which is a maximum of three half-lives. Due to the L/D ratio an unsharpness of $9.82-14{\mu}m$ and a magnification of 1.0003 were given. After digitizing an image of SR film, the ballooning gap of the plug was discernible by an H/V filter of image processing. The gap size of the ballooned element, K174L-3, is equal to or greater than 1.2 mm. The development of a transfer method played a pivotal role in developing high burn-up of Wolsung and PWR nuclear fuel type.

• 대한두개안면성형외과학회지
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• 제13권2호
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• pp.99-103
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• 2012

Purpose: Many surgical methods for reconstruction of orbital floor fracture have been reported, which include subciliary approach, transconjunctival approach, transantral and transnasal endoscopic approach, etc. The purpose of this study is to demonstrate a surgical technique and analyze the results of transnasal endoscopic approach with Foley catheter ballooning without implantation of artificial surgical material through subciliary approach. Methods: Between February 2007 and November 2010, 29 orbital floor fracture patients, who had no herniated muscles through bone fragments, were treated through transnasal endoscopic approach with Foley catheter ballooning. Under the endoscopic view, the operator identified the opening of maxillary sinus. After widening of the opening using forceps, the operator reduced the fragmented bone with curved suction tip. Thereafter, 18-Fr Foley catheter was inserted. Four weeks after the operation, the catheter was removed. Results: Preoperatively, 6 patients had diplopias, 4 patients had limitations of extraocular motions and 3 patients had enophthalmos. After removal of the Foley catheter 4 weeks after the operation, 2 patients had diplopias, 1 patient had a limitation of extraocular motion, 1 patient has an enophthalmos and 1 patient had numbness on the cheek. These symptoms were resolved about 6 months after the surgery. Conclusion: The operative technique of Foley catheter ballooning through transnasal endoscopic approach without implantation of the artificial surgical material through subciliary approach can be considered one of the appropriate techniques for orbital floor fracture.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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• pp.26-27
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• 2006

The fundamental mechanical characteristics under tensile and bending deformations of hermetically-sealed reinforced Bi-2223 tape and CTOP processed Bi-2223 tape were examined at 77K. Also, the Tensile strain dependence of the critical current, $I_c$, was obtained at 77K and self-field. The reinforced hermetic tape showed higher tensile strength and a better Tensile strain tolerance than the CTOP processed tape. For bending tests, a rho-shaped sample holder was used giving multiple bending strains. in increasing order. In the same case under bending deformation, the hermetic tape showed a higher bending strain tolerance than the CTOP processed tape. This higher strength of the hermetic tape can be attributed to the thick hardened copper reinforcement layer.

• 한국초전도ㆍ저온공학회논문지
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• 제7권4호
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• pp.4-9
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• 2005

The degradation behavior of the critical current $(I_c)$ of Bi-2223 superconducting tapes under pressurized liquid nitrogen were investigated using a newly developed p-shaped sample holder which gives a series of bending strains to a sample. Three kinds of commercially available multi-filamentary Bi-2223 superconducting tapes were used. At atmospheric pressure, the Ie degradation behavior depended on the manufacturing process undergone by each tape. The tapes externally reinforced or densified by over pressure showed better bending strain tolerance than the Ag alloy-sheathed Bi-2223 tape. But these tapes showed a significant $I_c$ degradation when pressurized to 1 MPa in liquid nitrogen. For all samples, after depressurization to atmospheric pressure from 1 MPa, the Ie was completely recovered to its initial values at atmospheric pressure. When the samples were subjected to a thermal cycle wherein the tape was warmed up to room temperature after being depressurized from 1 MPa, it was found that the larger degradation of $I_c$ occurred at the regions where significant ballooning occurred, such as $0\%\;and\;0.2\%$. However, an improved ballooning damage tolerance was observed in the highly-densified tape.