• 한국터널지하공간학회 논문집
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• 제20권5호
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• pp.887-897
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• 2018

수직구와 수평 터널 주위 지층 변화, 지진파 방향성이 접속부의 동적 거동 특성에 미치는 영향을 연구하였다. 유한 요소 기반의 MIDAS GTS NX 프로그램을 이용한 3차원 시간이력 해석을 통해 검토하였다. 연구결과 연약지반에서 장주기의 지진파가 수평 터널 방향으로 발생하였을 때 접속부 상부에서 최대 변위가 발생하는 것으로 나타났다. 또한 수직구와 수평 터널의 서로 다른 거동 및 지층 경계면의 영향으로 인해 응력집중 현상이 발생하여 문제가 될 수 있음을 확인 할 수 있었다. 연구 결과는 수직구와 수평 터널의 접속부 구조물 내진설계를 위한 기초자료로 활용 될 수 있을 것으로 기대된다.

• 대한조선학회논문집
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• 제42권3호
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• pp.259-267
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• 2005

The effects of hull flexibility on shaft alignment are growing as ship sizes are increased mainly for container carrier and LNG carrier. In order to consider hull flexibility on a propulsion shafting system, standardization of ship service conditions is necessary because hull deformation is continuously variable according to ship service conditions. How to summarize ship service conditions is suggested based on practically applicable four viewpoints : hull, engine, loading and sea status. Effects of the external forces acting on a ship propulsion shafting system are generally commented. Several design criteria regulated by classification societies are pointed at issue which seems to have Insufficient technical background. A qualitative verification is carried out to point out the invalidity of the assumption of effective supporting position. In this work, an elastic nonlinear multi-supporting bearing system is introduced as a key concept of the elastic shaft alignment. Hertz contact theory is proved to be more proper one than projected area method in calculation of the nonlinear elastic stiffness of the bearing, The squeezing and oil film pressure calculations in the long journal bearing like an after stern tube bearing are recognized as a necessary process for elastic shaft alignment design.

• Clinics in Shoulder and Elbow
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• 제22권2호
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• pp.87-92
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• 2019

Background: This study was conducted to compare the radiological and clinical outcomes of internal fixation using a Polarus humeral nail for treatment of a humeral shaft fracture according to fracture types. Methods: From 43 patients, 13 were excluded and 30 patients were included. The 30 patients were divided into 2 groups: 15 in group I (Orthopaedic Trauma Association/Arbeitsgemeinschaft $f{\ddot{u}}r$ Osteosynthesefragen classification type A and B) and 15 in group II (type C). The mean age was 63.1 years (range, 20-87 years), and mean follow-up period was 2.3 years (range, 1.0-6.1 years). The causes of injuries were as follows: 12, traffic accidents; 14, simple slips; 2, simple falls; 2, contusions after lower energy trauma. Radiological and clinical evaluations were performed. Results: Radiological union was confirmed by plain anteroposterior and lateral radiographs on average of 5.0 months in group I, and 8.4 months in group II, respectively. Differences between the two groups were statistically significant (p<0.01). The clinical union value was 1.6 in group I, and 2.0 months in group II, but these values did not differ significantly (p=0.441). The mean Korean shoulder scoring system scores were 89.7 and 90.6, which did not differ significantly (p=0.352). Conclusions: Intramedullary nailing using the Polarus humeral nail is considered to be a good treatment modality for all types of humeral shaft fractures. Additionally, the Polarus humeral nail can be an optimal choice for the treatment of complex type fractures such as segmental or comminuted humeral shaft fractures.

• Applied Microscopy
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• 제44권2호
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• pp.47-52
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• 2014

Fine structural characteristics of eggs (nits) found on the scalp hairs of Korean children were observed with scanning electron microscopy. An egg is structurally composed of four parts: the cementum, nit body, operculum, and aerophyle. The total length of an egg is about 1.5 mm. The glue secreted from the female louse completely surrounds the 1 mm hair shaft and forms the cementum. The thickness of the cementum at the end of the nit body was found to be more than 5 times the thickness at the end toward the scalp. The nit body is shaped like a goblet with a very smooth surface. The operculum and aerophyles are located at the apiculus area. In the circular operculum, there are 10 aerophyles concentrated on the side of the hair shaft surface that are shaped like a dome. Three aerophyles in the center are surrounded by 7 aerophyles. Each aerophyle is dome shaped with a diameter of $65{\mu}m$ and a respiratory pathway with a $15{\sim}25{\mu}m$ opening at the center. On the cut surface where the operculum is separated as the egg hatches, long grooves about $1{\mu}m$ thick are uniformly formed transversely. These long grooves facilitate the separation of the operculum through body expansion at the time of hatching.

• Applied Microscopy
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• 제33권3호
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• pp.215-222
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• 2003

모발의 관리와 미용을 위해 일상생활에서 $40{\sim}170^{\circ}C$의 온도로 가해진 열에 의해 손상된 모발의 외부형태와 미세구조를 주사전자현미경과 투과전자현미경으로 관찰하였다. 우리가 일상생활에서 오랜 기간 동안 헤어드라이기를 사용하였을 때 모발에는 다음과 같은 형태적 변화가 일어나서 손상되는 것을 확인하였다. 첫째, 소피의 바깥층을 이루고 있는 비늘이 들떠지는데 이것은 소피세포의 세포사이 막복합체가 분리가 되면서 일어났다. 이어서 모발의 소피층은 떨어져 나가고 피질이 노출되었다. 이차적으로 피질의 각화세포들은 macrofibrl 사이가 찧어지면서 공기 중에 노출되었고 이들 사이에 멜라닌과립들이 산재되어 있었다. 결과적으로 건조한 고열의 바람은 모발의 수분을 제거시키고 모발을 딱딱하게 만들어 탄력성을 상실시키는 것을 확인하였다. 결국, 손상된 모발은 거칠고 불규칙한 표면을 나타내며 광택을 상실하게 되는 것을 확인하였다.

• 대한골관절종양학회지
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• 제17권2호
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• pp.87-90
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• 2011

골모세포종은 뼈를 생성하는 드문 양성 종양으로 척추에 주로 발생하지만 장골에서 병적 골절을 발생시키는 골모세포종에 대한 보고는 거의 없다. 저자들은 상완골 간부에 골모세포종으로 인한 병적 골절에 대하여 종양은 소파술을 시행하였고 병적 골절에 대해서는 골수강내 금속정을 이용한 고정술을 시행하여 안정적인 골유합을 얻을 수 있었다. 저자들은 이처럼 보기 드문 상완골 간부애 골모세포종으로 인한 병적 골절을 진단하고 치료하는 경험을 하였기에 이에 관한 증례를 보고하고자 한다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 추계학술대회 논문집
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• pp.464-469
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• 2012

발전소에 있어서, 발전소가 높은 신뢰성이 있기 위해서는 안정적인 회전체의 동적 운동이 확보되어야 하므로, 장기간 안전하게 운전하기 위하여 축 진동은 매우 중요한 요소중의 하나이다. 하지만 어느 복합발전소에서는 오일 탄화물에 의한 비정상적인 1X 성분의 축 진동 상승으로 가스터빈이 여러번 정지되었다. 본 논문에서는 가스터빈 Exhaust 케이싱 베어링에서 발생한 이상진동에 대하여 어떻게 현장조치를 하였는지를 기술하였다.

• 융복합기술연구소 논문집
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• 제6권1호
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• pp.23-26
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• 2016

DC motor shafts have several defects such as double cut, deep scratch on surface, and defects in diameter and length. The deep scratches are due to collision among the other shafts. So the scratches are long and thin but their orientations are random. If the smallest enclosing box, i.e. oriented bounding box for a detective point group is found, then the size of the corresponding defect can be modeled as its diagonal length. This paper proposes an suface inspection algorithm for the DC motor shaft using the oriented bounding box. To evaluate the proposed algorithm, a test bed is made with a line scan CCD camera (4096 pixels/line) and two rollers mechanism to rotate the shaft. The experimental result on a pre-processed image with contrast streching algorithm, shows that the proposed algorithm sucessfully finds 150 surface defects and its computation time (0.291 msec) is enough fast for the requirement (4 seconds).

• 플랜트 저널
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• 제4권4호
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• pp.56-61
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• 2008

The phenomena of oil whip in steam turbines take place for the unbalance force between a rotor shaft and bearing oil film. The several parameters that affect onset of oil whip have been well known. However, the major parameter of oil whip is shaft mis-alinement. A oil whip causes the high vibration and the shutdown of rotor system. We mostly stop the steam turbine to adjust a shaft re-alinement concerning oil whip. In this case, it needs many costs for maintenance and long shutdown times. In this study, we study and observe the oil whip of the 300MW steam turbine in many years and we conduct the field test for another steam turbine for reducing vibration from oil whip. The results of this study are that a oil whip takes place with a particular rotating speed or a particular turbine output and the oil temperature change is a very effective method for on-line oil whip treatment.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 춘계 학술발표회 논문집
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• pp.486-493
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• 2006

This paper deals with the procedure and the results on the dynamic loading tests of two large diameter - long drilled shafts (diameter=2.0m, length=75m) which were embedded into weathered rocks through thick soft marine clays and sandy gravels. Prior to the real dynamic loading test, the numerical simulation for the test procedure was performed to check the structural stability of the main pile body using equivalent static elastic analysis and the application of the hammer system using WEAP (Wave Equation Analysis of Pile Driving). Through these preliminary analyses the dynamic loading tests on large diameter - long drilled shafts have been successfully achieved.