• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.8
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• pp.1883-1897
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• 1993

Interactive computer-aided analysis of mechanical systems has recently been undergoing an evolution due to highly efficient computer graphics. The industrial implementation of state-of-the-art analytical developments in mechanisms has been facilitated by computer-aided design packages because these rigid-body mechanism analysis programs dramatically reduce the time required for linkage design. This paper proposes a component modular approach to computeraided kinematic motion analysis for general planar multiloop mechanisms. Most multiloop mechanisms can be decomposed into serveral components. The kinematic properties (position, velocity, and acceleration) of every node can then be determined from the kinematic analysis of the corresponding component modules by a closed-form solution procedure. In this paper, 8 types of modules are defined and formulations for kinematic analysis of the component modules are derived. Then a computer-aided kinematic analysis program is developed using the proposed approach and the solution procedure of an example shows the effectiveness and accuracy on the approach.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.75.2-75.2
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• 2011

고온고압에서 운전되는 IGCC용 분류층 석탄가스화기는 석탄에 포함된 회 성분을 대부분 용융 슬래그 형태로 가스화기 벽을 타고 흘러내리게 하여 가스화기 하부로 배출시킨다. 이러한 용융 슬래그를 원활하게 배출시키는 것은 가스화기의 안정적인 운전에 있어서 매우 중요하다. 본 연구에서는 슬래그 층 내의 물질수지, 운동량 및 에너지 보존을 고려하여 석탄가스화기내의 슬래그 거동을 해석할 수 있는 모델 식을 유도하였다. 유도된 슬래그 거동 모델 식들을 적용하고 가스화기의 형상을 고려하여 가스화기 내부에서의 슬래그 거동을 해석하였다. 또한 슬래그 물성치들인 슬래그 점도, 슬래그 비열, 슬래그 밀도, 슬래그 열전달 계수 등을 슬래그의 조성 변화에 따라 별도로 산정하여 슬래그 해석의 입력 데이터로 사용하였다. 슬래그에 첨가되는 석회석의 비율을 해석의 주요 변수로 사용하여 가스화기 하부에서 용융 슬래그 및 고체 슬래그 두께, 용융 슬래그 층 내부에서의 슬래그 점도분포 및 슬래그 속도분포 등 슬래그 거동의 주요 특성들을 예측하였다. 해석결과로 석탄에 석회석의 첨가량을 증가시키면 슬래그의 임계점도온도(temperature of critical viscosity)와 점도가 낮아지므로 가스화기 벽면에서의 용융 슬래그의 유동속도는 빨라지며, 고체 슬래그와 용융 슬래그의 두께가 감소하는 것을 정량적으로 확인할 수 있었다.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.21 no.1
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• pp.27-31
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• 2010

Mild vocal fold hypomobility is a common finding of which clinical significance is incompletely understood. Recently, electrophysiologic investigations have shown that vocal fold hypomobility is a continuum of neurogenic dysfunction ; partial denervation (paresis), complete denervation (paralysis), and variable degrees and patterns of reinnervation. Despite a sound pathophysiological basis for its existence, interest in and acceptance of the diagnosis of vocal fold paresis is relatively recent. Vocal fold paresis may be a relatively common and often overlooked condition that can be difficult to diagnose since laryngoscopy does not reliably distinguish innocent laryngeal asymmetry from hypomobility caused by paresis. Although not entirely free from error, laryngeal electromyography seems to hold more promise as a means of reliable diagnosis than laryngoscopy, and should be employed systematically in the evaluation of suspected paresis. The means to help most patients with paresis already exists in the repertoire of interventions developed to treat paralysis. However, since the vocal fold retains substantial movement, more conservative treatment strategy is recommended as a first line of treatment. The authors reviewed the representative reports of vocal fold paresis and summarized the controversies and consensus regarding the vocal fold paresis.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.7 no.4
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• pp.83-90
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• 1987

The applications of reduced integration technique, addition of nonconforming modes, and their coupling to the Mindlin plate elements to improve their basic behavior are reviewed and the establishment of a series of new plate elements by combined use of these schemes are presented in this paper. The element formulation is based upon quadratic Mindlin plate concept. The results obtained by new elements converged to the exact solutions very rapidly as the mesh is refined and showed reliable solutions even for severely distorted meshes. The new elements have the requisite numbers of zero eigenvalues associated with rigid body modes to avoid the spurious zero energy modes. These elements are shown to be applicable to the wide range of plate problems, giving a high accuracy for both thick and thin plates.

• Journal of the Society of Naval Architects of Korea
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• v.29 no.4
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• pp.66-74
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• 1992

A panel method in the spirit of Hess & Smith(1962), and also of Dawson(1977) was developed to compute the wave resistance of a submerged, or a surface piercing, body moving in the water of finite depth. As a boundary condition on the free surface what is called the Poisson equation is used, while Yasukawa(1989) chose the Dawson equation for which the double-body flow is regarded as the basic one. In order to satisfy the boundary condition on the bottom surface automatically, the sum of a Rankine source and its image with respect to the bottom surface is chosen as the Green function, and hence the singularity is distributed only on the body and on the free surface thereby decreasing the required number of panels dramatically, compared to that of Yasukawa, without the consequential loss of accuracy. Calculations were done for a submerged sphere and for the Wigley hull, and the results are compared with other existing analytical and numerical data.

• Journal of the korean Society of Automotive Engineers
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• v.9 no.3
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• pp.16-22
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• 1987

직접분사식 디젤기관의 성능과 배기가스 문제에 여향을 주는 실린더 내에서의 연소형태는 크게 연료분사계와 흡입공기 유동계 두 가지에 의해 결정된다. 즉 분사율, 부사시기, 분무형태와 같은 분사계의 특성과 공기선회, 스퀴시(squish), 난류와 같은 공기 유동 특성에 의하여 연소형태가 결 정된다. 이러한 복잡한 연소형테를 기관 특성에 맞게 조정한다는 것은 대단히 어려운 문제인데 이것은 연료화 공기의 혼합이 연소실형상과 흡기계의 형상에 큰 영향을 받으며 연료가 액체 상 태로 연소실내로 들어와 분무과정을 통하여 증발이 되어야만 연소가 가능하기 때문이다. 특히 흡입공기 유동계에 있어서 현재의 직접 분사식 대젤기관의 흡입구 형상은 흡입공기의 운동에너 지에 모멘트를 가하여 연소실내에서 공기의 선희(swirl)를 발생시켜 줌으로써 연료와 공기의 혼 합기를 형성시키는 Helical type이 많이 이용되고 있다. 그러나 기관 성능과 배기가스 특히 NOx는 상반관계를 이루기 때문에 연소실내로 들어오는 흡입공기의 선희강도(swirl ratio)를 너무 강하게만 한다고 하여 좋은 결과를 얻을 수는 없다. 따라서 설계하고자 하는 각 기관에 있어서 요구되는 성능과 배기가스 문제를 만족하는 흡입공기의 선희강도가 얻어질 수 있도록 흡입구 형상을 설계한다는 것은 많은 연구와 경험이 요구되고 있다. 본 자료에서는 직접분사식 디젤기 관에 있어서 흡입공기의 최적 선희강도에 대한 설정방법과 흡입구 형상 설계를 위한 설계 이론 및 정상류 Rig test상에서의 흡입공기 선희강도의 평가방법을 소개하고자 한다.

• Restorative Dentistry and Endodontics
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• v.37 no.2
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• pp.110-113
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• 2012

Complications resulting from condylar fracture include occlusal disturbance due to loss of leverage from temporomandibular joint (TMJ). In general, closed reduction with active physical training has been performed, and under favorable circumstances, adaptation occurs in attempt to restore the articulation. The patient in this case report had unilateral condylar fracture accompanied with multiple teeth injuries, but he was left without any dental treatment for 1 mon which led to unrestorable occlusal collapse. Fortunately, delayed surgical repositioning of dislocated maxillary anterior teeth followed by consistent long-term physical training has been proved successful. Normal occlusion and satisfactory remodeling of condyle were obtained on 10 mon follow-up.

• Journal of Korean Orthopaedic Sports Medicine
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• v.5 no.1
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• pp.63-68
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• 2006

Purpose: To assess the effectiveness of the Locking compression plate (LCP) after open reduction for the treatment of the displaced clavicular shaft fracture, the clinical and radiologic outcome of the patients who were managed with the LCP for internal fixation after open reduction has been analyzed. Materials and Methods: We reviewed 26 cases with a displaced clavicular shaft fracture treated by internal fixation using Locking compression plate after open reduction between May 2003 and November 2004. The patients were followed up for at least six months period, and final postoperative outcome was evaluated using clinical results based on Kang's criteria, radiologic signs of fusion. Results: All fractures united by an average of 9.3 weeks without delayed union and showed fast recovery of motion fraction and shoulder function. In addition,24 cases without the fractures of proximal humerus recovered to normal range of shoulder notion within 2.9 weeks. Clinically, according to Kang's criteria, the outcome was good or better in 22 patients. The complications included shoulder joint dysfunction in two cases and keloid formation in one case, and no other complications were observed. Conclusion: The internal fixation using LCP for the treatment of displaced clavicular shaft fracture is a safe, reliable method of treatment, with few complications, and offers rapid recovery of shoulder joint function and bone union.

• Journal of Yeungnam Medical Science
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• v.3 no.1
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• pp.361-366
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• 1986

Fracture of the carpal scaphoid bone is the most common fracture of the carpus. Unfortunately. nonunion are common since the symptoms do not alert patients to seek early medical treatment and the diagnosis is easily missed. Fracture of the scaphoid is a common condition whose management remains controversial. The conservative treatment has many complications, these include inability to work while in plaster, stiffness of the wrist afterwards, muscle wasting, weakness and malunion. So various operative treatments of scaphoid fracture have been developed. Open reduction by use of screws suggested by Maclaughlin first in 1954. In 1984 a new and simple operative technique has been developed to provide rigid internal fixation for all types of fractures of the scaphoid by T.J. Herbert. This involves the use of a double-treaded bone screw which provides good fixation that, after operation, a plaster cast is rarely required and most patients are able to return to work within a few weeks. Authors have experienced 10 cases of scaphoid fracture and accomplished good result in all cases by internal fixation using Herbert screw. The results are as follows : Of these 10 fractures, 2 were fresh fractures and 8 were non unions of scaphoid fracture. In nonunion cases, the time interval between fracture and operation was from 5 months to 5 years. The postoperative immobilization period was average of 4 weeks. Short period of immobilization achieved early functional recovery of the wrist. The bony unions in roentgenogram were seen from 3 months to 9 months after operation. In 2 cases the fracture gap was seen after 9 months. But in these cases the symptoms such as pain and range of motion of wrist were improved.

• Clinics in Shoulder and Elbow
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• v.13 no.2
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• pp.202-208
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• 2010

Purpose: In this study we introduced minimal invasive plate osteosynthesis (MIPO) and analyzed clinical outcomes to determine the effectiveness of this intervention in proximal humerus fractures. Materials and Methods: We studied 27 patients including 16 cases with a 2-part fracture, 10 cases with a 3-part fracture, and 1 case with a 4-part fracture. Clinical outcomes were evaluated using UCLA score, KSS score and recovery of range of motion. Time to union and humerus neck-shaft angle change were estimated by radiologic assessment. The average follow up period was 19 months. Results: UCLA scores were "excellent" for 15 patients, "good" for 12 patients. The mean KSS score was 91.4 at final follow-up. The average shoulder range of motion was $167.2^{\circ}$ in forward elevation. Bone union occurred by 14.1 weeks postoperatively. Humerus neck-shaft angle recovery was "excellent" in 24 patients and "moderate" in 3 patients. There were no complications such as axillary nerve paralysis, deep infection, or subacromial impingement of the plate. Conclusion: MIPO for proximal humerus fractures is an effective procedure if performed with sufficient understanding of the anatomical structures. MIPO leads to minimized dissection of soft tissue, low complication rates and early recovery of range of motion.