• Proceedings of the KWS Conference
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• 2007.11a
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• pp.118-120
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• 2007

• Proceedings of the KWS Conference
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• 1995.04a
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• pp.58-61
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• 1995

• Maxillofacial Plastic and Reconstructive Surgery
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• v.17 no.1
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• pp.60-72
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• 1995

Temporomandibular joint ankylosis is the movemental obstacle of mandible which depend on proliferation of bony or fibrous tissue in temporomandibular joint structure by various causes. In order to treat this, various surgical methods have been performed, but no operative methods have been produced consistently successful results. This research has been performed to the patients who had been operated due to temporomandibular joint ankylosis by studying classification, cause, onset, duration, anesthesia and treatment method, symptom, change of mouth opening, complication through medical record, X-ray, follow-up for being a help to proper selection of treatment method and evaluation of prognosis. The author obtained the following results by analyzing 44 cases among patients who had been operated due to temporomandibular joint ankylosis during 8 year hospitalization from 1986 to 1993 in Dept. of Oral & Maxillofacial Surgery of Seoul National University Hospital. 1. The occurrence was in the order of below 10, 20's, 10's, 30's. The average of occurrence was 12.95. Illness period was 50.0% within 10 years and 50% beyond 10 years. The average period of illness was 13.33 years. 2. Trauma occupied 54.5% of causes and inflammation occupied 45.5%. Men had more occurrences due to trauma and there was no difference in case of inflammation. 3. In nasotracheal intubations for general anesthesia, the cases of using fiberoptic laryngoscope occupied 40.9%, direct or blind nasotracheal intubation occupied 40.9% and the cases of using tracheostomy occupied 18.2%. 4. In operative approaching methods, submandibular & preauricular approach were mainly applied, and in operative methods, high condylectomy(Group I) occupied 11.4%, arthroplasty without interpositional material following condylectomy or gap ostectomy(Group II) occupied 11.4%, with interpositional material following high condylectomy (Group III) occupied 40.9%, and using condylar reconstruction following condylectomy or gap ostectomy(Group IV) occupied 36.6%. 5. In change of mouth opening reformed after surgery, Group III showed the best result of average 23.5mm, Group IV showed 16.3mm, Group I showed 14.9mm and Group II showed 10.2mm of reformation. Summarizing the results as written above, it is considered that early treatment is important as soon as possible in Temporomandibular joint ankylosis. It is recommended in surgical method what can lead to postoperative early movement maintaining anatomaical & functional form, and then the development of various surgical methods will be requested.

• The Journal of the Korean dental association
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• v.19 no.4 s.143
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• pp.375-380
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• 1981

Unilateral bony ankylosis of temporomandibular joint is not extremely rare. Treatment in all cases should be surgical. Considerable difficulty has been encountered by surgeons in the judgment of the planning of the treatment for anklosis; either by gap arthroplasty or by interposition arthroplasty. A recent review of the literautre reveals that many authors reported more of the interposition arthroplasty treatment because of no recurrence and the excellent results obtained. This 22-year-old Korean female, who had suffered from unilateral temporomandibular joint recurrent anklosis, was received an operation of ramus osteotomy followed by interpositional arthroplasty with using of thin gold plate. She formerly was received condylectomy twice at the age of 8 and 9, under the diagnosis of unilateral bony ankylosis due to trauma. My experience with alloplasty in unilaterally recurrent ankylosed T-M joint is presented here for her general and oral functional condition proved to be satisfactory after 4 years follow-up.

• Journal of electromagnetic engineering and science
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• v.15 no.4
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• pp.199-205
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• 2015

An electromagnetic band gap (EBG) metamaterial construction is presented. A construction of a multipath mitigating ground plane, based on the EBG metamaterial is described. A method of the ground plane application and installation, which provides the multipath mitigating without spoiling antenna element phase center stability, is suggested and explained. A designed construction of GNSS antenna module, which contains the multipath mitigating ground plane, made from the presented EBG metamaterial and installed in the described way is shown and parameters of the antenna module are provided.

• Journal of Engineering Education Research
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• v.22 no.5
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• pp.3-12
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• 2019

Due to the expansion of rolling admissions and diversification of college admissions, the widening gap between the level of scholastic ability and academic performance is the reality of college education. Thus, based on the incoming class of College A, this study analyzes the correlation between incoming students who enrolled in a college mathematics course during their first semester. Through this analysis, this study searches for a way to efficiently instruct students from various learning backgrounds when enrolled in the same course. Also, this study searches for a solution to lower the deviation of college mathematics' academic performance among engineering majors by examining the efficiency of a joint managed college mathematics curriculum.

• Journal of Korean Tunnelling and Underground Space Association
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• v.5 no.4
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• pp.361-370
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• 2003

In this study, the performance of water tightness of water expansional sealing material and gasket was evaluated. The water tightness test was performed varying the type of inner pressure condition, for which the water expansional sealing material was inundated for 5 days to evaluate the ability of water tightness. In order to carry out this test, we made use of two types of water expansional sealing material; general type and combined type with non-expansional rubber. In the case of gasket, EPDM gasket and complex gasket sticked to the water expansional sealing material were applied. The performance of water tightness depended on the construction defect and the deformation of segment. The construction defect and segment deformation were generally expressed by gap and offset of the construction joint. The results, of tests showed that the performance of water tightness was largely influenced by the gap between segments. Management criteria of gap and offset were proposed.

• Journal of Advanced Marine Engineering and Technology
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• v.30 no.5
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• pp.623-628
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• 2006

Laser material processing is a very fast advancing technology for various industrial applications. because of many advantages. Its major advantage of less and controlled heat input has been exploited successfully for the very critical application of aluminium alloy welding. This study suggested the occurrence source of weld-defects and its solution methods in a welding of lithium ion battery by pulsed Nd:YAG laser. In experiment. battery case has changed over joint geometry from welding of side position to flat one. In the case of a electrolyte injection hole in order to seal it. welding is carried out after pressing Al ball. At this time. an eccentric degree. contact length and gap are worked as a major parameters. As improving the method of Al ball pressing. it was able to reduce an eccentricity. increase the contact length and decrease gap. As a results of a experiment. a sound weld bead shape and crack-free weld bead can be obtained.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.06a
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• pp.339-343
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• 2005

Laser material processing is a very fast growing technology for various industrial applications, because of many advantages. Its major advantage of less and controlled heat input has been exploited successfully for the very critical application of aluminium alloy welding. This study suggested the occurrence source of weld-defects and its solution methods in a welding of lithium ion battery by pulsed Nd:YAG laser. In experiment, battery case has changed over joint geometry from welding of side position to flat one. In case of a electrolyte injection hole in order to seal it, welding is carried out after pressing Al ball. At this time, an eccentric degree, contact length and gap are worked as a major parameters. As improving the method of Al ball pressing, it was able to reduce an eccentricity, increase the contact length and decrease gap. As a results of a experiment, a sound weld bead shape and crack-free weld bead can be obtained.

• Journal of Welding and Joining
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• v.23 no.4
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• pp.73-80
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• 2005

Arc blow being occurred by Electro-Magnetic force(EMF) during the electric arc welding prevents the formation of a sound weldment. In this study, the effects of arc position, groove size, tack weld and base plate on the EMF in a butt-joint welding of mild steel plate are analyzed by a computer simulation based on the finite element method. The EMF can be numerically identified to be caused by a difference of the magnetic flux-density between ahead of and behind the arc in case that the workpiece locates asymmetrically around the uc. When there exists an air gap of groove ahead of the arc in the welding direction, the similar magnetic force has been producted regardless of the arc position and the gap size. The tack weld alleviates the magnetic force to about one fourth at the finish end of the workpiece. The magnetic force can be also significantly reduced with the base plate to about one fifth at the start end of the workpiece containing a tack weld.