• 대한두개안면성형외과학회지
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• 제18권4호
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• pp.249-254
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• 2017

Background: Lower eyelid incisions are widely used for the orbital approach in periorbital trauma and aesthetic surgery. In general, the subciliary approach is known to cause disposition of the lower eyelid by scarring the anterior lamella in some cases. On the other hand, many surgeons believe that a transconjunctival approach usually does not result in such complications and is a reliable method. We measured positional changes in the lower eyelid in blowout fracture repair since entropion is one of the most serious complications of the transconjunctival orbital approach. Methods: To measure the positional changes in the lower eyelids, we analyzed preoperative and postoperative photographs over various time intervals. In the analysis of the photographs, marginal reflex distance 2 ($MRD_2$) and eyelash angle were used as an index of eyelid position. Statistical analyses were performed to identify the significance in the positional changes. All patients underwent orbital reconstruction through a transconjunctival incision by a single plastic surgeon. Results: In 42 blowout fracture patients, there was no statistical significant difference in the MRD2 and eyelash angle. Furthermore, there were no clinical complications, such as infection, hematoma, bleeding, or implant protrusion, during the follow-up periods. Conclusion: The advantages of the transconjunctival approach for orbital access include minimal scarring and a lower risk of eyelid displacement compared with other approaches. Based on these results, we recommend the transconjunctival approach for orbital exposure as a safe and reliable method.

• 대한기계학회논문집B
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• 제31권5호
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• pp.491-498
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• 2007

Flame characteristics of a methane-air premixed flame stabilized in a heat-regenerative small combustor were investigated experimentally. A small combustor having two counter-current shallow channels and a combustion space at one side was developed. In which the channel-gap was less the ordinary quenching distance of a stoichiometric methane-air premixed flame. Two design parameters of channel gap and thickness of the middle wall, which is located between two channels for unburned and burned gases, were varied. Flame stabilization conditions and characteristic flame behaviors were experimentally examined. Conclusively, Blowout conditions were governed mostly by the scale of the combustion space, and flashback conditions into the channel are dominated by the channel gap. Surface temperatures of the combustor were between 100 to 500$^{\circ}C$. Additionally, two distinctive flame stabilization modes of radiation and well-stirred?reaction were observed and their applicability was discussed.

• 한국구조물진단유지관리공학회 논문집
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• 제18권1호
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• pp.40-47
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• 2014

최근 토목구조물의 보수 보강 및 리모델링시 구조부재를 부착시키거나 고정하는데 있어서 시공의 유연성 및 용이성으로 후설치 앵커의 사용량이 증가하고 있는 실정이지만 현재 우리나라에서는 설계자와 시공자가 신뢰할 수 있는 명확한 설계기준이 없는 상태로서 외국의 설계기준에 의존하고 있는 실정이다. 무근콘크리트에 매입된 앵커에 인발하중이 작용할 때 앵커의 다양한 파괴모드는 콘크리트 파괴, 쪼갬파괴, 강재파괴, 뽑힘파괴 및 측면파괴가 발생한다. 이것은 강재의 인장 강도, 콘크리트 강도, 매입 깊이, 앵커 간격, 연단거리와 인접 앵커의 존재에 따라 달라진다. 본 연구에서는 매입깊이, 앵커간격 및 연단거리를 변수로 한 후설치 콘크리트 세트앵커의 인발파괴실험을 통하여 무근콘크리트에 매입된 후설치 세트앵커의 인발거동에 미치는 영향을 규명하는 것을 그 목적으로 한다.

• 대한두개안면성형외과학회지
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• 제19권4호
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• pp.248-253
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• 2018

Background: The presence of enophthalmos is an important determinant in the decision of orbital wall fracture surgery. We proposed eyelid drooping as a new anthropometric diagnostic measure and analyzed whether eyelid drooping is associated with enophthalmos. Methods: This retrospective study was performed from January 2014 to December 2016. A total of 75 patients with blowout fractures were studied. One experimenter measured the degree of enophthalmos using a Hertel exophthalmometer at 1 week after trauma and at 3 months after surgery. The height change of the upper eyelid was measured using the marginal reflex distance (MRD) on both sides, and the degree of eyelid drooping was calculated by comparing the two lengths. We analyzed statistically the correlation between enophthalmos and eyelid drooping. Results: We found a highly significant correlation between the degree of enophthalmos and the reduction rate of MRD (RRM, as an indicator of eyelid drooping) at 1 week after trauma (r= 0.845). Approximately 2.0 mm of enophthalmos was associated with a 30.8% reduction in MRD on the affected side as compared with the normal side. At 3 months after surgery, patients showed improved eyelid appearance, with a moderate association between enophthalmos and RRM. Conclusion: We demonstrated that the degree of enophthalmos, measured using an exophthalmometer, is associated with a change in the height of the upper eyelid. Thus, upper eyelid drooping can be used as another indicator for orbital wall fracture surgery. Compared with conventional methods, measurements of eyelid drooping are easy to perform, offering a great advantage and understanding to the patient.