• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.3
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• pp.338-345
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• 2000

A model testing has been performed to investigate the flow characteristics of a vortex chamber, which plays a role of a flow switch and passively controls the discharge flow rate. This method of passive flow control is a matter of concern in the design of advanced nuclear reactor systems as an alternative to the active flow control to provide emergency water to the reactor core in case of postulated accidents like LOCA (Loss-Of-Coolant Accident). By changing the inflow direction in the vortex chamber and varying the flow resistance inside the chamber, the vortex chamber can control passively the injection flowrate. Fundamental characteristics such as discharge flow rate and pressure drop of the vortex chamber are measured, and its parametric effects on the performance of the vortex chamber are also systematically investigated.

• Journal of the Microelectronics and Packaging Society
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• v.18 no.1
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• pp.41-47
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• 2011

Currently, there is widespread adoption of silicon-based technologies for the implementation of radio frequency (RF) integrated passive devices (IPDs) because of their low-cost, small footprint and high performance. Also, the need for high speed data transmission and reception coupled with the ever increasing demand for mobility in consumer devices has generated a great interest in low cost devices with smaller form-factors. The UWB BPF makes use of lumped IPD technology on a silicon substrate CSMP (Chip Scale Module Package). In this paper, this filter shows 2.0 dB insertion loss and 15 dB return loss from 7.0 GHz to 9.0 GHz. To the best of our knowledge, the UWB band-pass-filter developed in this paper has the smallest size ($1.4\;mm{\times}1.2\;mm{\times}0.40\;mm$) while achieving equivalent electrical performance.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.4
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• pp.31-38
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• 2011

In this paper, we propose an autonomous Indoor lighting control system in which indoor lighting devices are autonomously controlled such that electricity bills are minimized in our daily life. Our focus is to utilize Passive Infrared (PIR) sensors to detect the presence of human being indoor and automatically to control indoor lighting electric devices. A control algorithm is also devised to control the whole system. We justify the proposed system by demonstrating specific applications in our everyday life. Cost survey and experimental results also demonstrate the efficiency of the proposed system in real life.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.2
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• pp.82-88
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• 2009

Power capacitor is generally installed to compensate for the low power factor of inductive load But it has been used as passive filter to reduce harmonics generated by the power conversion device. Passive filter is composed by the series connection of reactor and capacitor. Because passive filter has play an important role on the absorber of harmonics, it takes voltage and current stress, follows partially burned on flamed and degradation, finally it has not guaranteed normal life. In this paper, we analyzed the effect that passive filter installed at the source side of PWM inverter is received by harmonics absorption.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.669-672
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• 2004

The thin-film passivation technology using the poly-para-xylylene (parylene) was applied to polymer electroluminescent devices. The fabricated device shows a good luminescent characteristic of maximum 11640 cd/$m^2$. The measured lifetime was reached up to 28 hours, which means the effectiveness of the passivation. Applying the parylene thin-film passivation technique, 10${\times}$10 passive matrix display system was implemented and obtained some still images.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.406-407
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• 2009

In this paper, presents the Wilkinson power divider used integrated passive device (IPD) technology with excellent performance for personal communication services (PCS). The insertion loss of this power divider is 0.4 dB and the port isolation greater than 25 dB over the entire band. Return losses input and output ports are 18 dB and 19 dB, respectively. The power divider based on SI-GaAs substrate is designed within die size of about $0.775\times0.53\;mm^2$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.50-51
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• 2009

This paper presents integrated passive device (IPD) based on Wilkinson power divider. The simulated 2-way power divider has the insertion loss of 3.123 dB, output isolation of -24.576 dB, input return loss of 26.415 dB, and output return loss of 33.478 dB. The power divider is based on IPD process design simulation at 2.5 GHz for WiMAX (Worldwide Interoperability for Microwave Access) applications. The chip size of power divider is $1\;\times\;1.2\;mm^2$, which is under fabrication.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.1
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• pp.56-65
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• 2011

A new hybrid mount system is proposed for microvibration control in a high-tech factory. The mount consists of an airspring as a passive device and a piezostack actuator as an active device. The two devices are connected in series. Some numerical simulations and experimental tests are carried out to evaluate isolation performance of the mount system comprising of four proposed hybrid mounts. As a control logic, the specific algorithm is adopted for considering multiple target frequencies of excitation based on a Filtered-X LMS algorithm. The results are compared with isolation performance of the passive airspring mount system. It is confirmed that the proposed hybrid mount system has great performance on microvibration.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.12
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• pp.166-172
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• 1995

A novel passive TE/TM polarization mode converter is fabricated by using poled polymer waveguides. The optic axis of the poling induced waveguide is slowly rotated by using a slowly varying structure of poling electrodes. Thus the polarization conversion is achieved as the guided mode propagates through the waveguide. The proposed device is simulated by a full vectorial beam propagation method (VBPM) for anisotropic medium. For the rotation length of 1 mm, the TE polarization of the guided mode is successfully converted to the TM polarization with negligible loss. Based on the simulation results, we fabricated the polarization converter which is tested by using 1.3 $\mu$m laser diode. TE to TM mode conversion is observed with a polarization extinction ratio higher than 30 dB, and the excess loss is less than 1 dB. The polarization conversion is relatively insensitive to wavelength since the device contains no periodic structures. These devices are easier to fabricate than others containing periodic structures.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1482-1483
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• 2008

This report describes the design, fabrication and experimental results of an implantable micro pressure regulator. It consists of three silicon substrates, a glass substrate, and a PDMS layer. Silicon and glass substrates are fabricated by using bulk micro machining and sandblasting. The PDMS layer is used as a intermediate layer for Si-Si and Si-glass bonding processes. This micro regulator is a key component of the portable drug delivery systems for low power consumption. The device has some advantages, such as a passive type device, no power consumption, and simple structure.