• 한국해양공학회지
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• 제13권3B호
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• pp.65-72
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• 1999

A deep-ocean mining riser pipe is subjected to floating vessel motion as well as environmental forces arising from currents and waves. The dynamic analysis is carried out for a deep-ocean mining riser pipe by using a finite element method. The vortex shedding which excites risers in a direction perpendicular to the flow and induces transverse response is considered. It is demonstrated that transverse displacements due to vortex shedding is greatly increased in lock-in regions. The result of this study is compared with other results having good agreements.

• Wind and Structures
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• 제25권4호
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• pp.329-342
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• 2017

This work presents a static and free vibration analysis of functionally graded metal-ceramic (FG) beams with considering porosities that may possibly occur inside the functionally graded materials (FGMs) during their fabrication. A new displacement field containing integrals is proposed which involves only three variables. Based on the suggested theory, the equations of motion are derived from Hamilton's principle. This theory involves only three unknown functions and accounts for parabolic distribution of transverse shear stress. In addition, the transverse shear stresses are vanished at the top and bottom surfaces of the beam. The Navier solution technique is adopted to derive analytical solutions for simply supported beams. The accuracy and effectiveness of proposed model are verified by comparison with previous research. A detailed numerical study is carried out to examine the influence of the deflections, stresses and natural frequencies on the bending and free vibration responses of functionally graded beams.

• Smart Structures and Systems
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• 제19권4호
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• pp.441-448
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• 2017

This paper uses the four-variable refined plate theory for the free vibration analysis of functionally graded material (FGM) rectangular plates. The plate properties are assumed to be varied through the thickness following a simple power law distribution in terms of volume fraction of material constituents. The theory presented is variationally consistent, does not require shear correction factor, and gives rise to transverse shear stress variation such that the transverse shear stresses vary parabolically across the thickness satisfying shear stress free surface conditions. Equations of motion are derived from the Hamilton's principle. The closed-form solutions of functionally graded plates are obtained using Navier solution. Numerical results of the refined plate theory are presented to show the effect of the material distribution, the aspect and side-to-thickness ratio on the fundamental frequencies. It can be concluded that the proposed theory is accurate and simple in solving the free vibration behavior of functionally graded plates.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 1989년도 추계학술발표회논문집
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• pp.9-12
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• 1989

ABSTRACT -- Recently, a method of magnetically-enhanced discharge columns is considered to increase the luminous efficacy of discharge lamps, which is based upon the face that the diffusion motion of charged particles in the discharge column strongly depends on the applied magnetic fields. This study investigates the effect of applied transverse magnetic fields on the light output of low-pressure Hg-Ar discharge. As a result, it is found that the electric field in the positive column increases according to the applied megnetic field, which causes an increase in the total light output. And this effect is much more pronounced upon the spectral line originating form the higher levels.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.852-854
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• 2000

The paper is described about the statatic and dynamic characteristics analysis of Transverse Swithed Reluctance Motor(TSRM). To investigate the nonlinearity of magnetic circuit, parameters of the modeling are computed by the finite element method as functions of input current and angular displacement. The current, torque, back EMF and output power wave of TSRM are simulated from the motion equation by MATLAB/Simulink.

• PNF and Movement
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• 제6권3호
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• pp.29-35
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• 2008

Purpose : To describes the important aspects of the foot and ankle movement and function used when git and balance strategy. Method : The foot and ankle was a very important roles in the lower limb movement and gait. This study summarizes the physiologic movement of knee to the PNF lower extremity patterns. Result : The ankle joint composed of the talocural joint, the subtalarl joint, transverse tarsal joint, talocalcaneonavicular joint. The onset of dorsiflexion muscle activity starts in pre swing gait patterns. First contract muscle is the extensor hallucis. Activity of tibialis anterior and extensor digitorum longus quickly follows in mid swing gait phase. During stance phase, the soleus and gastrocnemius muscle provided plantar flexor torque, which muscle reacts quickly to restrain ankle dorsiflexion, and contributes modulated control of the ankle motion in gait patterns. Conclusions : The understanding of ankle kinematics, could provide a good therapeutic approach for improving gait patterns in patients with various pathological condition.

• Bulletin of the Korean Chemical Society
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• 제21권3호
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• pp.310-316
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• 2000

Molecular dynamics simulation studies for thermotropic liquid crystalline systems conposed of rodlike molecules with 6 Lennard-Jones interaction sites wre performed in NPT ensemble. Within the range of temperature studied, the system exhibited isotropic and smectic phase. For the characterization of the smectic phase, we examined the structure of the liquid crystalline phase via the radial distribution function, its longitudinal and transverse components to the director, and other orientational correlation function, its longitudinal and transverse components to the director, and other orientational correlation functions. In the smectic A phase, our results showed a large anisotropy in translational motion (i.e.,$D_⊥ >> D_∥$), and the decay of the collective orientational correlation function of rank two became slower than that of the single particle orientational correlation function of rank one. Comments on the spontaneous growth of orientational order directly from the isotropic phase are given.

• 대한기계학회논문집
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• 제17권7호
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• pp.1719-1730
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• 1993

This paper presents the theoretical natural frequencies of out-of-plane deformable ring based on the variables such as out-of-plane deflection, torsional rotation and shear rotation. Based on the same variables, a finite element eigen analysis is carried out by using the $C^0$-continuous, isoparametric element which has three nodes per element and three degrees-of-freedom at each node. Numerical experiments are peformed to find the integration scheme which produces accurate natural frequencies, natural modes and correct rigid body motion. The uniformly reduced integration and the selective reduced integration give more accurate numerical frequencies than the uniformly full integration, but the uniformly reduced integration produces incorrect rigid body motion while selective reduced integration does correct one. Therefore, the ring element based on the three variables which employes selective reduced integration is recommended to avoid spurious modes, to alleviate the error due to shear locking and to produce correct rigid body motion, simultaneously.

• Archives of Plastic Surgery
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• 제35권5호
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• pp.527-532
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• 2008

Purpose: Transverse type or volar oblique type of defect of thumb tip can be covered by Moberg flap or second toe pulp free flap. We compared these two methods in functional result, patients' satisfaction, and sensation, etc. to find a better way to cover the defect of the thumb tip. Methods: From 2003 to 2006, we chose the patients randomly with preoperative pictures. The patients had the defect of the thumb tip which is either transverse or volar oblique type. The 6 patients were treated with Moberg flap and other 6 patients were treated with second toe pulp free flap. We have analyzed the results by 2 point discrimination, side pinching power test, pulp to pulp pinching power test, pain scales (visual analogue scale), satisfaction scales of the patients (functional and aesthetic), the degree of the range of motion, etc. Results: All flaps survived without any complications. In the cases of Moberg flaps, the value of static 2 point discrimination test was 5.6 mm, and the value of moving 2 point discrimination test was 4.8 mm. In the cases of second toe pulp free flaps, the values were 9.6 mm and 9.3 mm. In the cases of Moberg flaps, the value of the Side pinch power test was 6.6 kg, 4.4 kg. In the case of second toe pulp free flaps, the values were 4.8 kg and 2.5 kg. The value of aesthetic satisfaction scale of the patients in Moberg flaps was 5.6, the value of functional satisfaction scale of the patients was 3.6. In cases of second toe pulp free flaps, the values were 5.6 and 3.6. The active range of motion of Interphalangeal joint in the cases of Moberg flaps was 46.6 degree, and the active range of motion of metacarpophalangeal joint was 55 degree, in the cases of second toe pulp free flaps, the values were 36.6 degree and 59 degree. Conclusion: As a result, when the defect of the thumb tip is transverse or volar oblique type, we suggest that the operators choose Moberg flap to cover the defect of the thumb tip.

• 대한인간공학회지
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• 제31권2호
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• pp.345-352
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• 2012

Objective: The aim of this study is to evaluate the accuracy and reliability of Spine-Pelvis Monitor(SPM) that was developed to measure 3-dimensional motion of spine and pelvis using tilt sensor and gyro sensor. Background: The main cause of low back pain is very much associated with the task using the low back and pelvis, but no measurement technique can quantify the both spine and pelvis. Method: For testing the SPM, 125 angles from three anatomical planes were measured three times in order to evaluate the accuracy and reliability. The accuracy of SPM in measuring dynamic motion was evaluated using digital motion analysis system. The motion pattern captured by two measuring methods was compared with each other. In result, the percentage error and Cronbach coefficient alpha were calculated to evaluate the accuracy and reliability. Results: The percentage error was 0.35% in flexion-extension on sagittal plane, 0.43% in lateral bending on coronal plane, and 0.40% in twisting on transverse plane. The Cronbach coefficient alpha was 1.00, 0.99 and 0.99 in sagittal, coronal and transvers plane, respectively. Conclusion: The SPM showed less than 1% error for static measurement, and showed reasonably similar pattern with the digital motion system. Application: The results of this study showed that the SPM can be the measuring method of spine pelvis motion that enhances the kinematic analysis of low back dynamics.