• Clinics in Shoulder and Elbow
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• 제21권4호
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• pp.234-239
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• 2018

Background: In elbow fracture-dislocation, partial excision of the comminuted radial head fracture that is not amenable to fixation remains controversial considering the accompanying symptoms. This study was undertaken to evaluate the results of radial head partial excision when the comminuted radial head fracture involved <50% of the articular surface in all-arthroscopic repair of elbow fracture-dislocation. Methods: Patients were divided into two groups based on the condition of the radial head fracture. In Group A, the patients had a radial head comminuted fracture involving <50% of the articular surface, and underwent arthroscopic partial excision. Group B was the non-excision group comprising patients with stable and non-displacement fractures. Follow-up consultations were conducted at 6 weeks and at 3, 6, 12, and 24 months after surgery. Results: In all, 19 patients (Group A: 11; Group B: 8) met the inclusion criteria and were enrolled in the study. At the final follow-up, all 19 patients showed complete resolution of elbow instability. No significant differences were observed in the range of motion, visual analogue scale score, and Mayo elbow performance score between groups. Radiological findings did not show any complications of the radiocapitellar joint. However, nonunion of the coracoid fracture was observed in 3 patients (Group A: 1; Group B: 2), without any accompanying instability and clinical symptoms. Conclusions: Considering that the final outcome is coronoid fracture fixation and lateral collateral ligament complex repair for restoring elbow stability, arthroscopic partial excision for radial head comminuted fractures involving <50% of articular surface is an effective and acceptable treatment for elbow fracture-dislocation.

• 한국결정성장학회:학술대회논문집
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• 한국결정성장학회 1996년도 The 9th KACG Technical Annual Meeting and the 3rd Korea-Japan EMGS (Electronic Materials Growth Symposium)
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• pp.179-200
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• 1996

The intrinsic instabilities of fluid flow occurred in the melt of the Czochralski crystal growth system Czochralski method, asymmetric flow patterns and temperature profiles in the melt have been studied by many researchers. The idea that the non-symmetric structure of the growing equipment is responsible for the asymmetric profiles is usually accepted at the first time. However further researches revealed that some intrinsic instabilities not related to the non-symmetric equipment structure in the melt could also appear. Ristorcelli had pointed out that there are many possible causes of instabilities in the melt. The instabilities appears because of the coupling effects of fluid flow and temperature profiles in the melt. Among the instabilities, the B nard type instabilities with no or low crucible rotation rates are analyzed by the visualizing experiments using X-ray radiography and the 3-D numerical simulation in this study. The velocity profiles in the Silicon melt at different crucible rotation rates were measured using X-ray radiography method using tungsten tracers in the melt. The results showed that there exits two types of fluid flow mode. One is axisymmetric flow, the other is asymmetric flow. In the axisymmetric flow, the trajectory of the tracers show torus pattern. However, more exact measurement of the axisymmetrc case shows that this flow field has small non-axisymmetric components of the velocity. When fluid flow is asymmetric, the tracers show random motion from the fixed view point. On the other hand, when the observer rotates to the same velocity of the crucible, the trajectory of the tracer show a rotating motion, the center of the motion is not same the center of the melt. The temperature of a point in the melt were measured using thermocouples with different rotating rates. Measured temperatures oscillated. Such kind of oscillations are also measured by the other researchers. The behavior of temperature oscillations were quite different between at low rotations and at high rotations. Above experimental results means that the fluid flow and temperature profiles in the melt is not symmetric, and then the mode of the asymmetric is changed when rotation rates are changed. To compare with these experimental results, the fluid flow and temperature profiles at no rotation and 8 rpm of crucible rotation rates on the same size of crucible is calculated using a 3-dimensional numerical simulation. A finite different method is adopted for this simulation. 50×30×30 grids are used. The numerical simulation also showed that the velocity and flow profiles are changed when rotation rates change. Futhermore, the flow patterns and temperature profiles of both cases are not axisymmetric even though axisymmetric boundary conditions are used. Several cells appear at no rotation. The cells are formed by the unstable vertical temperature profiles (upper region is colder than lower part) beneath the free surface of the melt. When the temperature profile is combined with density difference (Rayleigh-B nard instability) or surface tension difference (Marangoni-B nard instability) on temperature, cell structures are naturally formed. Both sources of instabilities are coupled to the cell structures in the melt of the Czochralski process. With high rotation rates, the shape of the fluid field is changed to another type of asymmetric profile. Because of the velocity profile, isothermal lines on the plane vertical to the centerline change to elliptic. When the velocity profiles are plotted at the rotating view point, two vortices appear at the both sides of centerline. These vortices seem to be the main reason of the tracer behavior shown in the asymmetric velocity experiment. This profile is quite similar to the profiles created by the baroclinic instability on the rotating annulus. The temperature profiles obtained from the numerical calculations and Fourier transforms of it are quite similar to the results of the experiment. bove esults intend that at least two types of intrinsic instabilities can occur in the melt of Czochralski growing systems. Because the instabilities cause temperature fluctuations in the melt and near the crystal-melt interface, some defects may be generated by them. When the crucible size becomes large, the intensity of the instabilities should increase. Therefore, to produce large single crystals with good quality, the behavior of the intrinsic instabilities in the melt as well as the effects of the instabilities on the defects in the ingot should be studied. As one of the cause of the defects in the large diameter Silicon single crystal grown by the

• 대한정형외과스포츠의학회지
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• 제8권2호
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• pp.102-108
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• 2009

목적: 슬관절의 후방 및 후외측 불안정성을 동종 아킬레스건 1개를 나누어 동시에 재건하는 수술 방법을 보고하고자 한다. 대상 및 방법: 슬관절의 후방 및 후외측 불안정성으로 수술받은 42명(45예)을 조사하였다. 남자 38명, 여자 4명이었고, 평균 나이는 39세였다. 수술 방법은 이식건으로 동종 아킬레스건을 2:1 넓이로 나누어 큰 것은 (${\emptyset}$ 10 mm) 후방십자인대, 작은 것은 (${\emptyset}$ 8 mm)은 후외측 재건술에 사용하였다. 먼저 후방십자인대에 대하여 관절경적으로 10 mm 신선 동결 동종 아킬레스건을 이용하여 후방십자인대 잔유물을 보존한 채로 경경골 접근법, 단일절개, 단일가닥방법으로 재건술을 시행하였으며, 후외측 불안정성에 대해서는 작은 이식건을 사용하여 변형된 8자 모양으로 고정하여 외측부 인대 및 슬와비골 인대를 재건하였다. 평균 추시 기간은 25개월이었다. 임상적 평가는 운동범위, 후방전위검사, 내반 부하 검사, 복와위 외회전(dial) 검사, Lysholm 점수와 Tegner 점수 및 후방전위 방사선검사로 평가하였다. 평균 추시기간은 25개월 이었다. 결과: 후방 전위 검사에서 수술 전 Grade II 5예, Grade III 40예, 추시관찰 시 정상 22예, Grade I 18예, Grade II 5예로 호전되었다. Dial 및 내반 부하 검사는 수술 전 45예 모두 양성에서 수술 후 36예에서 정상, 9예에서 양성을 보였다. 수술 후 10도 이상 굴곡제한을 보이는 경우가 3예 있었으나 나머지는 모두 정상 관절 운동 범위를 보였다. Lysholm 점수는 수술 전 평균 50점에서 수술 후 83점으로 호전되었다(p<0.05). Tegner 활동 점수는 수술 전 평균 2.1에서 수술 후 4.6점으로 호전되었다. (p<0.05). 슬관절 90도 굴곡위에서 시행한 후방 긴장 방사선 소견상 수술 전 평균 16 mm에서 수술 후 4.1 mm로 호전되었다. (p<0.05). 후방 전위 검사, 내반 부하 검사, dial 검사 등의 임상적 검사와 방사선 사진에서 후방 전위 정도를 비교하였을 때 모든 환자에서 수술 전보다 나은 결과를 보였다. 결론: 슬관절의 만성 후방 및 후외측 불안정성을 동종 신선 동결 아킬레스건을 이용하여 동시에 재건해 좋은 결과를 얻을 수 있다.

• 대한정형외과스포츠의학회지
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• 제4권1호
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• pp.49-54
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• 2005

목적: 무지 중수 수지 관절 척측 측부 인대 손상은 완전 파열 시 파열된 인대의 연속성을 방해하는 Stener 병변 때문에 수술적 치료인 탐색술 및 봉합술을 시행하고 있다. 저자들은 무지 중수 수지 관절 척측 측부 인대 손상에서 관절경을 이용, 진단과 치료를 시행하고 관절경적 수기에 대한 효용성을 알아보고자 하였다. 대상 및 방법: 무지 중수 수지 관절 척측 측부 인대 완전 파열로 관절경적 진단 및 치료를 받고 1년 이상 추시 가능하였던 13예를 대상으로 하였다. 평균 연령은 35.6세었다. 관절경으로 척측 측부 인대 손상, Stener 병변 등을 진단하였으며 관절경을 이용하여 치료하고 그 결과를 관절 불안정성 여부, 무지 의 집게력 파악력, 관절 운동 범위 등으로 판정하였다. 결과: 13예중 5예에서 Stener 병변이 관찰되었다. 전예에서 추시상 무지 중수 수지 관절의 불안정성이 없었고 무지의 집게력 및 파악력 은 건측의 92%, 94%로 회복되었으며 중수 수지 관절 운동 범위는 평균 52 도로 건측과 비슷하였다. 결론: 무지 중수 수지 관절 척측 측부 인대 손상에서 관절경 수기는 Stener 병변의 확진 및 치료를 가능하게 하고 연부조직 손상을 최소화시켜 조기 기능 회복을 기대할 수 있게 하는 유용한 치료 방법으로 사료되었다.

• The Journal of Korean Physical Therapy
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• 제14권4호
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• pp.172-182
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• 2002

Objectives: We did research in the cause of the Pitchers' injury and their recovery process to make a detailed injury list for the purpose of finding the cause of the Korean professional pitchers' injury and its classification. We drew the conclusion through the results as following. Methods: We posed a question to the 80 pitchers playing in the first team of the eight Korean professional baseball team and analyzed the 62 pieces of question paper except the paper having a mistake. We used SAS/PC statistical package in analyzing the data. Results: In the frequency of the pitchers' shoulder injury in the last three years, the injured of all the players were 61.3$\%$ and the injury free players were 28.7$\%$. The cause of the injury was 45.2$\%$ wrong pitching motion, which was the highest value. For the shape of a pain when injured, the reverberation ache feeling when he is hit in the weight commanded an absolute majority as 19.4$\%$. Those who had muscular pain were 17.7$\%$, which was felt mostly at the pitching motion. The most trouble name of the injured shoulder was bicepstendinitis as 16.1$\%$ while the injury of shoulder joint was the lowest as 1.6$\%$. As the most widely used treatment, 25.8 percent of all the players had taken an electronical thraphy after injury. 14.5 percent of the players who had an injury to the shoulder told that they have an operation and 85 percent of them didn't. As a sort of the operation, a repairing of labrum was 44.4 percent, which is the highest value and the 77.8 percent pitchers are performing a normal pitching through rehabilitation after the operation and 22.2 percent of them are undergoing rehabilitation training. Conclusion: The research have shown that the main cause of the injury, concerning the Korean professional pitchers throwing lots of ball in both matches and practices, is overuse syndrome, bad mechanism, muscle weakness and instability of balance. I think that the role of trainer, physical therapy, and team physician taking charge of the players' injury must learn physical test method by heart exactly to check up the state of the injury definitely at the initial phase. Moreover, when the cause of the injury part after a close examination is discovered, the scientific and good surgery is essential to the rehabilitation success and making a classification of shoulder instability is useful to make a operation plan as well as the players' rehabilitation, treatment.

• Clinics in Shoulder and Elbow
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• 제6권1호
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• pp.55-66
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• 2003

Background: The purpose of this study was to evaluated results of arthroscopic treatment of the traumatic recurrent unidirectional posterior subluxation. Materials and Methods: We treated twenty-seven patients who had traumatic recurrent unidirectional posterior subluxation of the shoulder by arthroscopic labral repair and posterior capsular shift and prospectively evaluated for a mean of thirty-nine months (range,24 to 85 months). Patients who had posteroinferior instability, multidirectional instability, atraumatic onset, or revision cases were excluded. There were twenty-five male and two female patients with the mean age of twenty-one years (range, 14 to 33 years). All patients were involved in sports activity. All had a significant traumatic event prior to the onset of the instability. Stability, motion, three objective measurement (UCLA, ASES, and Rowe scores) and two subjective measurements (pain and function visual analogue scale) were evaluated. Results: The most common finding in magnetic resonance image-arthrogram was separation of the posteroinferior labrum without displacement in 9 patients, In arthroscopic examination, all patients had one or more lesions in the posterior inferior labrum and capsule. The most common finding was incomplete stripping of the posterior inferior labrum (18 patients). The posteroinferior capsule subjectively appeared to be stretched in twenty-two patients. At follow-up, all patients had improved shoulder function and scores(p < 0.01). All patients had stable shoulder by subjectivel and objectivel measurements, except one patient who had recurrent subluxation. All but one patient with postoperative recurrence were able to return to their prior sports activity with little or no limitation. Twenty-four patients were graded as having more than 90％ of shoulder function. Their were twenty-one excellent, five good, and one fair UCLA. scores. Pain sore improved from 4.5 to 0.2 point(p : 0.0001). Mean loss internal rotation was one vertebral level. None had operative complications. Conclusion: In conclusion, treatment outcomes of the traumatic unidirectional recurrent posterior subluxation are consistently reliable with respect to the stability, pain relief, and functional restoration by the arthroscopic posterior capsular shift procedure.

• 한국통신학회논문지
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• 제38C권3호
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• pp.271-277
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• 2013

본 논문에서는 해상 무선 통신에서 선박의 흔들림으로 인한 신호의 편차문제를 해결하기 위한 새로운 접근방법을 제안하였고, 이를 위해 송신기는 육상에 있고, 수신기는 선박에 위치한 선박과 육상의 통신 시나리오를 가정하였다. 선박은 파도와 바람의 영향으로 인한 해양의 환경 때문에 안정적이지 못하고, 지속적으로 흔들리게 되는데, 이러한 선박의 흔들림은 선박에 위치한 안테나의 흔들림을 유발하여 신호의 수신을 불안정하게 만든다. 여기서, 우리는 신호가 높은 비트 에러율을 발생 수신기에서 상쇄되는 것을 예측할 수 있는데, 이러한 문제를 해결하기 위해 MIMO기술을 사용하여 해결하였다. 본 논문에서 여러 송신 안테나를 사용하는 빔포밍 기술을 구현할 것을 제안하였으며, 제안 방법에 대한 기술의 구현은 강건한 해상 통신 네트워크를 구성할 수 있다.

• 한국해양공학회지
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• 제26권4호
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• pp.77-85
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• 2012

A study was performed on the design of a mooring line to maintain the position of a floating WEC (wave energy conversion) system. The procedure to design a mooring line is set up and the safety of the designed mooring system is evaluated using commercial software, Orcaflex. The characteristics curve for one line is analyzed to determine the properties and pretension of a mooring line. While considering the ocean environmental condition and importance of a floating WEC system, a multi-line layout is determined. A 4-point mooring system with 4 lines shows the instability in the yaw motion of the floating WEC system under a designed ocean environmental condition. The redesigned 4-point mooring system with 8 lines is found to be safe on the condition of a harsh ocean environment. The floating WEC system with the redesigned mooring system also shows stable motion in surge and pitch under operating conditions. From a parametric study on the mooring line length, the extreme value of the mooring line tension is found to be very sensitive to the pretension and length of mooring line. The results of this study can contribute to the establishment of a design procedure for mooring lines.

• Journal of Astronomy and Space Sciences
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• 제20권3호
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• pp.205-216
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• 2003

회전안정화 로켓 모터를 이용하는 upper stage 위성체의 자세 불안정 현상을 연구하였다. 이 위성체는 대칭형의 본체와 내장된 유동질량으로 구성되며, 유동질량은 구진자로 모델링되었다. 종래의 선형모델이 갖는 단점을 보완하기 위해 정확한 시변 비선형 방정식을 사용하고, 본체 및 구진자 모두 회전 대칭축에 대해 정상상태에 있다고 가정하였다. 본 논문에서는 진자에 대한 준정상해(quasi-stationary solution) 및 공진조건을 파라미터의 함수로 결정하였다. 공진조건의 분석결과 유동질량은 계수자극 및 외부자극을 동시에 받으며, 자극을 받은 유동질량으로부터 에너지가 본체에 유입되면서 위성체는 불안정한 장동운동을 일으키는 것으로 확인되었다. 본 논문에서는 수치시뮬레이션 예시를 통하여 주어진 위성체 모델에 대해 발생가능한 공진조건에서 진자의 운동, 위성체 각 운동량 및 섭동모멘트의 관계 규명과 로켓모터 추진 후에 자세운동이 어떻게 변화하는가를 설명하였다.

• 한국소음진동공학회논문집
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• 제16권3호
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• pp.291-297
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• 2006

The BVI(blade vortex interaction) noise Prediction has been one of the most challenging acoustic analyses in helicopter aeromechanical Phenomenon. It is well known high resolution airloads data with accurate tip vortex positions are necessary for the accurate prediction of this phenomenon. The truly unsteady time-marching free-wake method, which is able to capture the tip vortices instability in hover and axial flights, is expanded with the rotor flapping motion and trim routine to predict unsteady airloads in forward and descent flights. And Farassat formulation 1-A based on the FW-H equation is applied for the noise prediction considering the blade flapping motion. Main objective of this study is to validate the newly developed prediction code. To achieve the objective, the descent flight condition of AH-1 OLS(operational loads survey) configuration is analyzed using present code. The predicted sectional thrust distribution and sectional airloads time histories show the present scheme is able to capture well the unsteady airloads caused by a parallel BVI. Finally, the predicted noise data, observed in two different positions where are 3.44 times of rotor radius far from the hub center, are quite reasonable agreements with the experimental data compared to the other analysis results.