• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.362-365
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• 2004

'Coil' occupies a much important position in delivering driving force of optical pick-up actuators. Up to now the main stream has been a winding coil type actuator, but actuators using FP-Coil(Fine Pattern Coil) have been considered for the more compacted and simple manufacturing process and have variously spreaded the application fields by product. We have tried to design actuators using PCB-Coil(Printed Circuit Board Coil) which has benefits in terms of price and manufacturing process. Especially this research has two main things those are to reduce the vibration of sub-resonance and to assure the do sensitivity in the performance of asymmetric optical pick-up actuator with PCB-Coil.

• 한국세라믹학회지
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• 제32권8호
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• pp.945-949
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• 1995

In order to investigate the performance of compression-type accelerometer on piezoelectric properties, PZT materials have been studied. The ring-shaped piezoelectric elements were prepared using commercial PZT powders by conventional ceramic process. Their estimated relative dielectric constant, piezoelectric charge constant (d33) and voltage constant (g33) values showed 390∼3400, (90∼593)×10-12 C/N and (19.5∼40.5)×10-3 V-m/N, respectively. The charge sensitivity of accelerometer is proportional to the piezoelectric charge constant value (d33) of PZT, but its voltage sensitivity is related with the piezoelectric voltage constant (g33). Since the mounted resonance frequency and sensitivity are dependent on the seismic mass as well as physical charateristics and size of PZT elements, the suitable considerations between two components are required for accelerometer's design.

• BMB Reports
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• 제31권1호
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• pp.101-105
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• 1998

Immunoassay of botulinum toxin (BTX) B type was investigated using two typed of biosensors: light addressable potentiometric sensor (LAPS) and surface plasmon resonance (SPR) sensor. Urease-tagged and immuno-filtration capture method have been used for LAPS. Tag-free and direct binding real-time detection method have been used for SPR sensor. The detection limit of sandwich assay format with LAPS was 10 ng/ml, which was the lowest among methods tested. SPR has the advantage of being more convenient because tag-free direct binding assay can be used and reaction time was reduced, regardless of low sensitivity. This result shows that sandwich assay format with LAPS can be used as an alternative method of BTX mouse bioassay which is known as the most sensitive method for the detection of BTX.

• Journal of Power Electronics
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• 제17권5호
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• pp.1382-1390
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• 2017

This paper presents a power supply for gate drivers, which uses a magnetic resonance wireless power transfer system. Unlike other methods where multiple antennas are used to supply power for the gate drivers, the proposed method uses a single antenna in an insulated receiver to make multiple mutually isolated power supplies. The power transmitted via single antenna is distributed to multiple power supplies for gate drivers through resonant capacitors connected in parallel that also block DC bias. This approach has many advantages over other methods, where each gate driver needs to be supplied with power using multiple receiver antennas. The proposed method will therefore lead to a reduction in production costs and circuit area. Because the proposed circuit uses a high resonance frequency of 6.78 MHz, it is possible to implement a transmitter and a receiver using a small-sized spiral printed-circuit-board-type antenna. This paper used a single phase-leg circuit configuration to experimentally verify the performance characteristics of the proposed method.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 추계학술대회 논문집
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• pp.257-261
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• 2011

The failures of local structure of marine medium-speed diesel engine occurred in durability test. The vibration response of the whole engine was in an acceptance level, but the local structures were broken. ODS test and vibration measurement were carried out in order to investigate the root cause of durability problem. These tests revealed that the root cause of failures was excessive vibration by $4.5^{th}$ resonance between engine body and local structure. The best solution to reduce the vibration response is to change the type of mount. After a rigid mount was replaced by a flexible mount, maximum vibration level dropped to 72%.

• 한국소음진동공학회논문집
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• 제16권1호
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• pp.89-100
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• 2006

This paper presents an analytical approach to describe the variation in the vibration characteristics such as the natural frequency of a piezoelectric transducer under static pre-pressure. The transducer considered in this paper is a bolt-clamped Langevin-type transducer, which consists of a couple of piezoelectric discs, a couple of metal blocks for added mass effect, and a bolt to tighten them. A new analysis model for the transducer has been developed by taking into account the contact area between the piezoelectric ceramic disc and the metal block. The variation of the resonance frequency due to the pre-pressure has been calculated and compared with measured results reported earlier.

• 한국자동차공학회논문집
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• 제5권3호
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• pp.66-75
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• 1997

Sound transmission from the luggage comparment into the car cabin is important in the viewpoint if exhaust and road noises of passenger cars. In this paper, acoustic modal coupling between passenger and luggage compartments through loudspeaker holes at parcel shelf is dealt with for a sedan type passenger car with rigid rear seat. For these purposes, a half-scaled model car is tested and computed by the indirect BEM. Predicted acoustic transfer functions are compared with experimental ones and they agree reasonably well. It is found that the fore-aft resonance frequencies of the passenger cavity in the absence of coupling holes are tend to shift to higher frequencies when the luggage compartment is coupled to the passenger cavity.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1996년도 추계학술대회 논문집
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• pp.270-273
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• 1996

This paper describes a type of piezoelectric transformer with improved design principles. It consists of a thin rectangular piezoelectric ceramic plate having two input electrodes and one output electrode. The length of each input and output electrode is nearly one third of that of piezoelectric transformer itself. In the driving section, the ceramic plate is poled in the thickness direction reversely with each other, and has electrodes on both main faces. The electric input near its fundamental resonance frequency is applied to the driving section in parallel and the output voltage from the generating section is connected to the resistor load. Its equivalent circuit is derived from the Mason\`s model. The frequency characteristics near the resonance frequency under no load have been investigated. Moreover, using this piezoelectric transformer we measured the LCD backlight characteristics.

• 동력기계공학회지
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• 제14권5호
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• pp.30-35
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• 2010

Recently, the large capacity draft fans in power plants had been changed to variable speed type to educe the power consumption. But the fan experienced the unexpected vibration at specific speed regions. In this study, the high vibration frequency of the fan was confirmed and the natural frequency of the rotor were measured and analyzed by FEM programs. It was analyzed that the vibration was caused by the resonance at the frequency, 30.7Hz. So, the rotor vibration characteristic was changed by adjusting the distance between the shaft bearings. It was conformed the high vibration was disappeared over the all operation speeds.

• 대한의용생체공학회:의공학회지
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• 제18권1호
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• pp.65-70
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• 1997

A human version of Korean total artificial heart(TAM) was designed basso on the magnetic resonance imaging(MRI) data To obtain accurate measurement or human thoracic structure including the valvular sited we analyzed the dimensions of the natural heart of healthy persons and cardiomyopathy(CM) patients. The MRI findings were analyzed to measure the volume of the thoracic cavity that would be occupied by the TAM. The design upgrade of the mechanical performed was also performed with the computer aided design(CAD) system to develop a new version of Korean TAH.