• 대한두개안면성형외과학회지
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• 제20권6호
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• pp.347-353
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• 2019

Most orbital surgeons believe that it's difficult to restore the primary orbital wall to its previous position and that the orbital wall is so thin that cannot be firmly its primary position. Therefore, orbital wall fractures generally have been reconstructed by replacing the bony defect with a synthetic implant. Although synthetic implants have sufficient strength to maintain their shape and position in the orbital cavity, replacement surgery has some drawbacks due to the residual permanent implants. In previous studies, the author has reported an orbital wall restoring technique in which the primary orbital wall fragment was restored to its prior position through a combination of the transorbital and transantral approaches. Simple straight and curved elevators were introduced transnasally to restore the orbital wall and to maintain temporary extraorbital support in the maxillary and ethmoid sinus. A transconjunctival approach provided sufficient space for implant insertion, while the transnasal approach enabled restoration of the herniated soft tissue back into the orbit. Fracture defect was reduced by restoring the primary orbital wall fragment to its primary position, making it possible to use relatively small size implant, furthermore, extraorbital support from both sinuses decreased the incidence of implant displacement. The author could recreate a natural shape of the orbit with the patient's own orbital bone fragments with this dual approach and effectively restored the orbital volume and shape. This procedure has the advantages for retrieving the orbital contents and restoring the primary orbital wall to its prior position.

• Journal of Astronomy and Space Sciences
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• 제35권4호
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• pp.227-233
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• 2018

This study presents the generation and accuracy assessment of predicted orbital ephemeris based on satellite laser ranging (SLR) for geostationary Earth orbit (GEO) satellites. Two GEO satellites are considered: GEO-Korea Multi-Purpose Satellite (KOMPSAT)-2B (GK-2B) for simulational validation and Compass-G1 for real-world quality assessment. SLR-based orbit determination (OD) is proactively performed to generate orbital ephemeris. The length and the gap of the predicted orbital ephemeris were set by considering the consolidated prediction format (CPF). The resultant predicted ephemeris of GK-2B is directly compared with a pre-specified true orbit to show 17.461 m and 23.978 m, in 3D root-mean-square (RMS) position error and maximum position error for one day, respectively. The predicted ephemeris of Compass-G1 is overlapped with the Global Navigation Satellite System (GNSS) final orbit from the GeoForschungsZentrum (GFZ) analysis center (AC) to yield 36.760 m in 3D RMS position differences. It is also compared with the CPF orbit from the International Laser Ranging Service (ILRS) to present 109.888 m in 3D RMS position differences. These results imply that SLR-based orbital ephemeris can be an alternative candidate for improving the accuracy of commonly used radar-based orbital ephemeris for GEO satellites.

• 대한두개안면성형외과학회지
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• 제13권1호
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• pp.29-35
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• 2012

Purpose: In surgical treatment of the medial orbital wall fractures, restoring the original position of the orbital wall is difficult in some cases. Under such condition, the orbital wall is often reconstructed with synthetic material, without bony reduction, which is considered to be the conventional reconstruction. The purpose of this study is to compare the outcomes of anatomical reconstruction, which restores the bony wall to the anatomical position, from that of the conventional reduction in the isolated medial orbital wall fractures. Methods: Thirty patients, who underwent reconstruction surgery for the isolated medial orbital wall fractures from March 2007 to August 2011, were reviewed retrospectively. The surgical outcomes of two groups, the conventional reconstruction group (15 patients) and the anatomical reconstruction group (15 patients), were studied in 2 measurements, a one day before and 6 months after the surgery. The changes of orbital volume were calculated by the images from a computed tomography scan and enophthalmos was measured by a Hertel exophthalmometer. Results: The orbital volume ratio was decreased by an average of 1.05% in the conventional reconstruction group, while in the anatomical reconstruction group, the ratio decreased by 5.90% (p<0.05). The changes in the Hertel scale were 0.20 mm in the conventional reconstruction group, and 0.70 mm in the anatomical reconstruction group. However, the difference in the Hertel scale was statistically insignificant (p>0.05). Conclusion: In conclusion, the anatomical reconstruction technique of the isolated medial orbital wall fracture results in a better outcome than that of the conventional reconstruction, in terms of restoring of the original orbital volume and anatomic position. Thus, it can be considered as a useful method for the isolated medial orbital wall fractures.

• 대한치과교정학회지
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• 제30권5호
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• pp.535-542
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• 2000

본 연구는 안면비대칭 환자의 natural head position(NHP)시 정면에서의 두부 또는 경추의 경사 정도를 알아봄으로써 교정환자의 임상검사시 비대칭의 진단에 도움이 되고자 시행되었다. 두드러진 전후방 골격 이상은 없으나 뚜렷한 좌우 안면비대칭을 보이는 성인 20명을 비대칭군으로, 좌우 대칭적인 외모와 비교적 정상교합을 보이는 성인 21명 을 대칭군으로 선정 한 다음 물방울 수평계를 이용하여 NHP 상태의 정모두부방사선사진을 촬영하고 투사도를 작성하였다. Crista galli와 anterior nasal spine을 연결한 선과 crista galli와 menton을 연결한 선이 이루는 각을 menton의 변위 정도로 정하고, 좌우 supra-orbital margin의 최상방점을 지나는 supra-orbital line과, 제1경추와 제4경추의 중심을 연결한 cervical line이 각각 true vertical line과 이루는 각을 계측한 다음 이들간의 상관관계를 비교 분석하여 다음과 같은 결과를 얻었다. 1. Supra-orbital line이 true vortical line과 이루는 각이 직각에서 벗어난 정도가 대칭군에 비하여 비대칭군에서 통계적으로 유의하게 크게 나타났다. 2. Cervical line이 true vertical line과 이루는 각은 통계적 유의차는 없었으나 비대칭군에서 더 큰 경향을 보였다. 3. 비대칭군에서 supra-orbital line이 true vortical line과 이루는 각이 직각에서 벗어난 정도는 menton의 변위 정도와 통계적으로 유의한 순상관관계를 보였다. 이상의 결과로 안면비대칭 환자는 menton의 변위를 보상하려는 방향으로 기울어진 NHP를 가지는 경향이 있음을 알 수 있었다.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2003년도 춘계학술발표대회 개요집
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• pp.155-158
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• 2003

Orbital GTA welding is used in the pressure pipe line of auto-mobile, LNG and plant piping. To weld the pipe line safely, to some extent, the back bead must be formed in the root pass. In the plate welding the back bead can be observed, but in the pipe welding, the back bead can not be observed directly. In the welding around circumference, the parameters such as gravity, surface tension and arc force are different at each position. And then D/B for welding condition at each position are required. We also studied about the setting of the optimum orbital welding condition by controlling heat input.

• Journal of Welding and Joining
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• 제27권1호
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• pp.71-78
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• 2009

In the circumferential welding of pipe, welding phenomenon changes with the position of pipe. Especially in the overhead position, back bead of vertical-up position would be sunk. To investigate the size of back bead and keyhole with the change of the flow rate of pilot and shield gas at each position, bead-on plate welds were conducted on 6mm thickness SS400 with inclined-up position. When the rest of welding conditions remained constant, the width of back bead was increased as the flow rate of pilot gas was increased. And back bead tended to convex as the flow rate of shield gas was increased.

• Journal of Astronomy and Space Sciences
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• 제6권2호
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• pp.91-100
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• 1989

정지 위성 궤도의 평균 궤도 요소를 비 특이점 궤도 요소 항으로 연구하였다. 실제 위성의 위치는 평균 궤도로부터 단주기 섭동 만큼 위성 위치가 진동하는데, 그 진동의 진폭은 1800m 이하이다. $e_c$ 와 $e_s$의 평균값도 얻었다.

• 치과방사선
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• 제19권1호
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• pp.25-29
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• 1989

The author has evaluated the panoramic image clarity of the midfacial anatomic structures in dry skull according to the skull position. The radiopaque markers were attached to the anatomic structures: infraorbial rim, upper and lower borders of zygomatic arch, pterygomaxillary fissure, lateral pterygoid plate, pyriform aperture of nasal cavity, lateral wall of maxilla, orbital floor, infraorbital foramen, and nasal floor. Position of the skull were divided into four groups. standard, 25mm forward, chin-down, chin-up position. The results were as follows: 1. The pyriform aperture of nasal cavity, lateral wall of the maxilla, orbital floor, infraorbital foramen and nasal floor did net cast any discernible image. 2. Nearly all images of midfacial structures were blurred in the chin-up position. 3. The forward position provided good visualization of the maxillary sinus. 4. The chin-down position provided good visualization of the zygomatic arch, pterygomaxillary fissue, and lateral pterygoid plate.

• 한국항해학회지
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• 제12권3호
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• pp.1-21
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• 1988

A Satellite -aided search and rescue system is expected for its many advantage of global coverage, instantaneousness and low cost. In this paper, a calculation method is proposed , by which a position of distress can be determined with doppler frequency received through an orbital satellite. First, an algorithm and program is developed for calculating the position of distress with the received doppler frequency of EPIRB(Emergency Position Indicating Radio Beacon) with the least square method. Then, position error caused by the drift of the transmitting frequency is evaluated. The evaluation is made by the simulation using NNSS satellite orbital elements and varying position of EPIRB, numbers of Doppler data and magnitudes of various errors. As the result, the availability of this program for a satellite-aided search and rescue system is confirmed and the bounds of expected positioning accuracy is clarified.

• 대한두개안면성형외과학회지
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• 제24권2호
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• pp.52-58
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• 2023

Background: Complex orbital fractures are impure orbital fractures because they involve the orbital walls and mid-facial bones. The author reported an orbital wall restoration technique in which the primary orbital wall fragments were restored to their prior position in complex orbital fractures in 2020. As a follow-up to a previous preliminary study, this study retrospectively reviewed the surgical results of complex orbital wall fractures over a 4-year period and compared the surgical outcomes by dividing them into groups with and without balloon restoration. Methods: Data of 939 patients with facial bone fractures between August 2018 and August 2022 were reviewed. Of these, 154 had complex orbital fractures. Among them, 44 and 110 underwent reduction with and without the balloon technique respectively. Pre- and postoperative Naugle exophthalmometer (Good-Lite Co.) scales were evaluated. The orbital volume and orbital volume ratio were calculated from preoperative and 6 months postoperative computed tomography images. Results: Among 154 patients with complex orbital fractures, 44 patients underwent restoration with the balloon technique, and 110 patients underwent restoration without it. The Naugle scale did not differ significantly between the two groups, but the orbital volume ratio significantly decreased by 3.32% and 2.39% in groups with and without the balloon technique and the difference in OVR was significantly greater in patients in the balloon restoration group compared with the control group. Postoperative balloon rupture occurred in six out of 44 cases (13.64%). None of the six patients with balloon rupture showed significant enophthalmos at 6 months of follow-up. Conclusion: The balloon rupture rate was 13.64% (6/44 cases) with marginal screw fixation, blunt screws, and extra protection with a resorbable foam dressing. Furthermore, we restored the orbital wall with primary orbital fragments using balloon support in complex orbital wall fractures.