• Journal of Power System Engineering
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• v.5 no.4
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• pp.38-43
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• 2001

This paper describes the effect of dynamic characteristics in tube line by external vibration conveying fluid with the power steering system. By the experimental analysis we found out that the factor of system vibration is the fluid-structure interaction of tube line. In fluid-filled tube system we study on the influence that the natural frequency of system and the frequency of wave motion produce upon through experiment. Experiments are modal test, frequency response function in continuous system, and vibrating tests when the system is driving with bolted clamping joint condition. From the results of the experimental studies, we obtained that the natural frequencies of system are very important than the wave induced vibrations. And we found that the tendency of system vibration level was decreased by bolting force, bolting condition and clamping distance.

• Journal of the Korean Society of Safety
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• v.15 no.3
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• pp.45-51
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• 2000

This paper studies the effect of vibrational characteristics of the various tubes analyzed though experiment. By an experiment analysis we found out that the factor of system vibration is fluid-structure interaction of tube line. In fluid-filled tube system we study on the influence that the natural frequency of system and the frequency of wave motion produce upon through three experiments. Three experiments are modal test on each tube, FRF in continuous system, and vibrating tests when the system is driving on. From the results of the experimental studies, we obtained that the natural frequencies of system are very important than wave induced vibrations. and according to the variation of configuration, the frequencies are different each other. And we found that though fluid passed away through the tube, the tendency of system vibration level was similar with the mode shape at the simple system.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.9
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• pp.694-701
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• 2002

In this paper, through the study on locations of structural transducers for active control of the radiated sound from the vibrating plate, the active structural acoustic control (ASAC) system is proposed. And, for the evaluation of the proposed location, the experiment of the active structural acoustic control is implemented using the multi-channel filtered-x LMS algorithm and an additional filter (Acoustic Prediction Filter) to estimate the radiated sound using the acceleration signals of the plate. The structural transducers are piezoceramic actuator (PZT) and accelerometer. PZT is used as an actuator to reduce the vibration and the radiated sound. To maximize the control performance, each PZT actuator is located at the position that has the largest control sensitivity of the plate bending moment in the direction of x and y coordinates and the optimal PZT location is validated experimentally. Also, to find the acoustic prediction filter accurately, two accelerometers are located at the positions that have the largest radiation efficiencies of the plate, and the proposed locations are validated by simulation using the Rayleigh integral. The multi-channel filtered-x LMS algorithm is introduced to control a complex 2-D structural vibration mode. Finding the locations of structural transducers for active structural acoustic control of the radiated sound, the active structural acoustic control (ASAC) system can be presented and validated by experiments using a real time control system.

• Applied Chemistry for Engineering
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• v.32 no.5
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• pp.556-561
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• 2021

Recently, iron oxide nanoparticles have been used as the subject of many studies on drug delivery system (DDS) due to their excellent magnetic properties and biocompatibility in response to external magnetic fields. In this study, hyaluronic acid-superparamagnetic microneedles (HA-SMNs) and carboxy methyl cellulose-superparamagnetic microneedles (CMC-SMNs) containing superparamagnetic iron oxide nanoparticles (SIONs) were prepared with HA and CMC as a matrix materials of MNs (microneedles). Various properties of SMNs were then investigated with scanning electron microscopy (SEM), superconducting quantum interference device-vibrating sample magnetometer (SQUD-VSM), frequency mixing magnetic detection (FMMD), and polymer/bio membrane. The SQUID-VSM measurements showed superparamagnetism of HA-SMNs and CMC-SMNs containing SIONs. The FMMD results demonstrated that the signal intensity changed significantly as the concentration of SIONs increased. In addition, SMNs exhibited the average skin permeability intensities on the bio membrane for HA-SMNs and CMC-SMNs were 92.5 and 98.5%, respectively. These results suggested that SMNs could be utilized as deliver materials for a TDDS and MR molecular imaging.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2009.04a
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• pp.125-129
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• 2009

본 연구에서는 동강성법을 이용하여 2자유도 진동시스템을 모델링하였다. 등가 모델을 구성한 후 Inertance의 크기에 따라 변화되는 시스템의 특성을 규명하였다. 2자유도 진동 시스템을 단일 모우드 소거에 적용할 경우 해석적인 설계 방법론을 1) 감쇠가 없는 경우 2) 1개의 감쇠기를 갖는 경우로 나누어 제시하였다.

• Journal of the Korean Institute of Telematics and Electronics
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• v.12 no.4
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• pp.41-45
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• 1975

기계계와 전기계 사이의 두 analogy로부터 mobility 회로와 impedamice회로를 얻었다. 이 두 기계기로에서 Ipedance와 nobility관계를 회로망리론을 근거로 비교 검토 하였고 이로부터 mobility 회로가 더 자연스럽고 기본적인 기계회로임을 구명하였다. 또한 impedance측정이 관찰점과 수에 따라서 가변성인데 비하여 mobility 측정은 불변성임을 보였다. Two mechanical networks, mobility network, and impedance network, are proposed md the relations between a mechanical system n4 their two mechanical networks are examined briefly. The mobility network is founed to be more natural of two networks. This paper also shows the invariant property of mobility elements in the measurement procedure.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.1038-1042
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• 2003

In order to evaluate dynamic impedance of a hand-arm system it is necessary to measure the hand-transmitted vibration and the reaction force at the same time while gripping the vibrating handle. In the study a device was developed to measure both the vibration and the force. The device consists of a measurement handle with four strain gauge and two accelerometers and a PC based control system with a program for the signal processing and evaluation of the hand-transmitted vibration and reaction force. The handle was installed on the vibration shaker so that it can move by the generated signal from the control system. As an application of the system dynamic reaction force and the frequency weighted acceleration at the handle attached to the shaker were measured at various grip force and feed force. This system will be very useful in the area of impedance measurement and the evaluation of performance of anti-vibration gloves.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.298-302
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• 2002

Equivalent volume estimation of the coupler and two coupled microphones has a key role in standard microphone pressure calibration. The equivalent volume of the microphone is determined by the dynamic characteristics of the diaphragm system and front cavity. Therefore the modal parameters of diaphragm system - natural frequency and damping fatter - should be measured explicitly for the estimation of the equivalent volume. The diaphragm system is composed of the vibrating diaphragm, back slit behind diaphragm, pressure equalization vent, and front cavity which are acoustically coupled. In the measurement, the electrostatic actuator was used to excite the system with the swept sine, and the frequency response was obtained. The close actuator in front of the diaphragm must influence the radiation impedance of the system, and then the modal parameters. From the measured frequency response, the natural frequency and the damping factor could be estimated with the Complex exponential method based on the Prony model and the zero crossing real and imaginary plot.

• Journal of Aerospace System Engineering
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• v.8 no.2
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• pp.33-39
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• 2014

Feathering spindle is one of the critical parts of the rotor system in the Smart Unmanned Aerial Vehicle(SUAV) that it was manufactured with special material, Maraging C300. During the initial ground and tie-down flight tests of the SUAV, surface of the feathering spindle contacting to the needle-roller bearings showed excessive wear and dent due to high vibrating loads transferred from the rotating blades. Gas nitriding process was applied to the bearing contact surface of the feathering spindle to increase surface hardness so as to improve the surface defects. This paper briefly presents the gas nitriding process adopted and the spindle quality improvements including wear and corrosion resistance.

• Journal of Advanced Marine Engineering and Technology
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• v.13 no.2
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• pp.21-42
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• 1989

Recently, multi-branced driving systems are often used for power station systems or for marine propulsion systems to save the initial cost, the man power and to improve the energy efficiency. As the multi-branched power system has a very complicated vibrating system, its analyzing method is quite different from the ordinary method for the single straight system. In this study, the multi-branched power system is reduced to derive equations of free vibration and some analytical methods are studied to solve these equations and computer programs are developed to calcuate their numerical solutions. And also, equations of forced-damped vibration of the multi-branched power system which involves diesel engines are derived and their solving methods are studied. Some computer programs are developed to get responses of the forced vibration with damping and their results are synthesized to get resultant responses. Finally, exciting forces of diesel engine and damping forces of power driving systems are appreciated to help field engineers by suggesting reasonable method of estimating their values.