• Journal of the Korean Arthroscopy Society
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• v.8 no.2
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• pp.89-93
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• 2004

Purpose: To evaluate the clinical stability and function after arthroscopic anterior cruciate ligament(ACL) reconstruction using fresh-frozen tibialis tendon allograft. Materials and Methods: Of the patients who underwent ACL reconstruction using tibialis tendon allograft from July 2002 to June 2003, thirty-one patients could be evaluated and the mean follow-up period was 19 months. Evaluations included were Lysholm knee score, 2000 International knee Documentation Committee (IKDC) subjective knee score, Lachman test, pivot shift test, KT-1000 arthrometer measurement and 2000 IKDC knee examination. Results: The mean Lysholm score was 88. Twenty-eight patients (90.3%) were good or exellent for the measured parameters. Twenty-seven patients(87.1%) was over 70 in IKDC subjective knee score. Thirty patients (96.8%) had 1+ firm end or negative Lachman test. 27 patients (87.1%) had a negative pivot shift. Thirty patients (96.8%) had less than 5mm difference of maximal manual difference by KT-1000 arthrometer. Twenty -nine patients (93.5%) were nearly normal or normal grade by 2000 IKDC knee examination. Complications were 1 case of failure and 1 case of infection. Conclusion: ACL reconstruction with the double-stranded fresh-frozen tibialis tendon allograft resulted in a reliable and predictable outcome after short-term follow-up.

• The Academic Congress of Korean Shoulder and Elbow Society
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• 2003.11a
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• pp.51-56
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• 2003

The trained examiner can gain considerable information from visual inspections of the elbow joint, Because much of the joint is subcutaneous, any appreciable alteration in the skeletal anatomy often is detectable. Gross soft tissue swelling or muscle atrophy is also early observed. Inspection and palpation of the medial and lateral epicondyles and the tip of the otecranon from an equilateral triangle with the elbow is flexed. Normally, the arc of flexion extension, although variable, ranges from about O to 140 degrees plus or minus 10 degrees. The posterolateral rotatory instability(PLRI) of the elbow is most common pattern of elbow instability. The lateral collateral ligament complex also includes a narrow but stout band of ligamentous tissue blending with the distal and proterior fibers of the capsule to insert distally on the crista supinatoris of the ulna. This is the lateral ulnar collateral ligament(LUCL). A clinical elbow pivot shift test confirms the PLRI. There are also two active apprehension signs.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2635-2643
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• 2011

Current freight electric locomotives (132 ton) of the eco-friendly and can carry large cargo logistics as a means of generation has increased the demand at home and abroad. Especially, Freight electric locomotives to increase the traction, it is easy to mass and rapid transport. In addition, Freight electric locomotives is no exhaust and low noise compared to diesel -electric locomotives and it can be eco-friendly transportation. CO_CO BOGIE of Freight electric locomotives has no the center pivot and Traction_Rod and Spring of CO_CO BOGIE is mounted on the body. These freight electric locomotives to be satisfied with the safety regulations. Carbody development satisfied Implementation of optimum body and collision is the focus. Accordingly, the different approach in the upper and lower carbody structure and interior and equipment placement is needed. On this paper, the contents give explanation of cases on carbody design composed of freight electric locomotives now developed and process of improvement by structure analysis and collision analysis.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.2
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• pp.187-194
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• 2016

Parametric study on the lever type dynamic anti-resonance vibration isolator (DAVI) is executed to introduce the system in the path of vibration transmission for the vibratory response attenuation. The effects of inertia and location of the lever on the system performances are investigated using FEA. The effects of other parameters such as ratio of lever lengths, ratio of masses and the location of pivot are studied with analytical approach. According to the results, all the parameters except lever location affect the system response in their own ways. Consequently, the optimal lever type DAVI for translational or rotational system can be efficiently designed by selecting system parameters using the procedure introduced in this study.

• Journal of Aerospace System Engineering
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• v.4 no.2
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• pp.21-25
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• 2010

Fatigue properties of composite materials are extremely important to design durable and reliable helicopter rotor blades. However, it is very difficult to apply conventional fatigue test loads in short period. Therefore, accelerating test speed and facilitating spectrum load realization are required. In this study, we have developed a fatigue testing method that uses a resonance of simply supported beam type blade specimen. This test consists in exciting the blade specimen with a frequency that corresponds to its natural frequency. In that case, the test specimen similar to a beam fixed between two pivot points starts vibrating and is significantly deformed. Resonant fatigue tests were performed by changing exciting vertical amplitude and frequency, and S-N curves of each composite materials were successfully obtained.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.10
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• pp.1238-1246
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• 2004

Momentum exchange theory has been generally used for an analysis of the regenerative turbomachines due to its direct description of the complicate circulatory flow. However, because its application is limited only to linear region and its model equations are incomplete on three variables, it needs further refinements. In the present study it is improved by introducing a central pivot of circulatory flow. Also, by assuming linear circulatory velocity distribution, mean radii of inlet and outlet flows through the impeller are newly suggested. By applying control volume analysis to both linear region and the acceleration region, the governing equation on the circulatory velocity is derived. As a result, systematic performance analysis on the entire region of the incompressible regenerative turbomachines can be carried out based on the proposed model equations.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.6
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• pp.97-108
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• 1996

A modeling technique is proposed for dynamic simulations of OHC valve trains with HLA(hydraulic lash adiuster). HLA is expressed by an air-oil mixture model considering HLA leak-down and aeraton effects. A compact nonlinear equation is derived which describe the short term dynamic behavior of the HLA. Valve spring is analyzed by a distributed parameter model including nonlinear characteristics in the spring surge phenomena. Global behavior of the remaining valve train is expressed by a lumped mass model. The experiental results prove that the simulation model developed here is accurate and useful for the dynamic simulations of OHC valve trains with HLA.

• Aerospace Engineering and Technology
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• v.9 no.2
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• pp.1-7
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• 2010

Fatigue properties of composite materials are extremely important to design durable and reliable helicopter rotor blades. However, it is very difficult to apply conventional fatigue test loads in short period. Therefore, accelerating test speed and facilitating spectrum load realization are required. In this study, we have developed a fatigue testing method that uses a resonance of simply supported beam type blade specimen. This test consists in exciting the blade specimen with a frequency that corresponds to its natural frequency. In that case, the test specimen similar to a beam fixed between two pivot points starts vibrating and is significantly deformed. Resonant fatigue tests were performed by changing exciting vertical amplitude and frequency, and S-N curves of each composite materials were successfully obtained.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.475-481
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• 1993

The objective of this study is to develope the reliability prediction model for Float Rated Integrating Gyroscope( :FRIG) at maximum loading. The equation of motion for FRIG is firstly derived to set up the reliability prediction model. To analysis reliability or all parts of the gyro is not easy due to their complicated structure. Therefore the failure parts are chosen by Failure Mode Effective Analysis (:FMEA). F.E.M is utilized to calculate loads for the selseced rotating assembly and pivot / jewel. The technical reliability is calculated by applying reliability design theory with these results and the performance reliability is sought through distribution estimation with error test data. The bulk reliability of gyroscope is sought by applying the two results. The present prediction results are compared with the accumulation time in good agreement.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1273-1276
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• 2005

A displacement magnification mechanism is usually employed in a nano-positioning stage to achieve a large stage motion. A lever mechanism is the most widely used displacement magnifying mechanism. For more large stage motion, double or multiple lever mechanisms can be used. In this case, a more accurate analysis model is needed. This study proposes a more reasonable analysis model for a multiple lever mechanism based on the single lever mechanism model. This paper describes that the high equivalent stiffness of the lever is the most important factor reducing the magnification ratio of the lever mechanism through increasing the deflection of the link and including the axial displacement of the pivot.