• ETRI Journal
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• v.27 no.5
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• pp.628-634
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• 2005

From AC analysis results utilizing a 2-dimensional device simulator, we extracted an AC-equivalent circuit of a grounded-gate NMOS (ggNMOS) electrostatic discharge (ESD) protection device. The extracted equivalent circuit is utilized to analyze the effects of the parasitics in a ggNMOS protection device on the characteristics of a low noise amplifier (LNA). We have shown that the effects of the parasitics can appear exaggerated for an impedance matching aspect and that the noise contribution of the parasitic resistances cannot be counted if the ggNMOS protection device is modeled by a single capacitor, as in prior publications. We have confirmed that the major changes in the characteristics of an LNA when connecting an NMOS protection device at the input are reduction of the power gain and degradation of the noise performance. We have also shown that the performance degradation worsens as the substrate resistance is reduced, which could not be detected if a single capacitor model is used.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.5
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• pp.54-59
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• 1995

We have proposed a novel self-aligned offset gated polysilicon TFTs device without an offset mask in order to reduce a leakage current and suppress a kink effect. The photolithographic process steps of the new TFTs device are identical to those of conventional non-offset structure TFTs and an additional mask to fabricate an offset structure is not required in our device due to the self-aligned process. The new device has demonstrated a lower leakage current and a better ON/OFF current ratio compared with the conventional non-offset device. The new TFT device also exhibits a considerable reduction of the kink effect because a very thin film TFT devices may be easily fabricated due to the elimination of contact over-etch problem.

• KIEAE Journal
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• v.2 no.4
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• pp.21-26
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• 2002

Modem architecture represent a great capitalistic, polishing, high-technology image to the public by design. As a result, glass architecture which show 'transmittance' in desinging play a leading part, consequently a role of machine is increasing in controlling an internal environment of building. These movement look like assisting an universal standard building disregarding a each nation's climate peculiarity, if glass building is applied by a proper external shading device. the shading device has a great effect on the reduction of cooling load energy, this research to propose the proper designing scheme of the fixed external shading device. The effect of proper external shading device on the cooling load is evaluated by the numeric simulation.

• Proceedings of the KIEE Conference
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• 1996.11a
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• pp.279-281
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• 1996

This paper deals with the two stage surge protection device by using varistor and LC low pass filter. Recently varistor alone has been used with overvoltage protection devices for the AC power mains and has same problems associated with high remnant voltage and noise. In this work, in order to improve the cutoff performance of surge protection device, the lightning surge protection device having two stage hybrid circuit for an AC single phase mains was designed and fabricated. Operation characteristics and surge clamping performance of the surge protection device in an $8/20{\mu}s$ surge current are investigated. As a consequence, it is found that the proposed two stage surge protective device for AC power mains has a variety of advantages such as a smaller clamping voltage, high frequency noise reduction and large clamping capacity.

• Journal of Wellbeing Management and Applied Psychology
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• v.4 no.3
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• pp.1-9
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• 2021

Purpose: This study was conducted to develop a module with higher removal efficiency and effectiveness by adapting two or more deodorization techniques for main cause of odor pollution exposed citizen living near water treatment facilities. Research design, data and methodology: To consider the standard, unity, electrical wire, compatibility of detachable device by installing two types of dry deodorization device within one module for easy replacement. Complex odor, H₂S, NH₃ were collected from sewage treatment facilities for evaluation of deodorization device. Results: Using the developed application in this study, removal efficiency of complex odor, H₂S, NH₃ were 93%, 100%, 82%, respectively. Conclusions: The H₂S removal efficiency of deodorization device was higher than bio-filter system, which were currently used by sewage treatment. Further, the device should be considered for use in efficient odor removal system.

• Journal of radiological science and technology
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• v.43 no.3
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• pp.169-176
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• 2020

Interventional radiology is performed under real-time fluoroscopy, and patients are exposed to a wide range of exposures for a long period of time depending on the examination and procedure. However, studies on radiation protection for patients during an intervention are insufficient. This study aims to evaluate the doses exposed during the intervention and the applicability of 3D printing materials. The organ dose for each intervention site was evaluated using a monte carlo simulatio. Also, the dose reduction effect of the critical organs was calculated when using a shielding device using 3D printing materials. As a result, the organ dose distribution for each intervention site showed a lower dose distribution for organs located far from the x-ray tube. It was analyzed that the influence of scattered rays was higher in the superficial organs of the back of the human body where x-rays were incident. The dose reduction effect on the critical organ using the 3D printing shield showed the highest testis among the gonads, and in the case of other organs, the dose reduction effect gradually decreased in the order of the eye, thyroid, breast, and ovary. Accordingly, it is judged that the 3D printed shield will be sufficiently usable as a shielding device for the radiation protection of critical organs.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.50 no.3
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• pp.342-350
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• 2014

An active stimulating device, such as a fluttering net or canvas attached to the end of a cod end generating a shaking motion, could help to encourage the escape of juvenile fish positioned passively near the net. Field fishing trials using a shrimp beam trawl were carried out to examine the effect on the reduction of juvenile fish or other discard catch by generating a shaking movement of the cod end using an unbiased cap-like round canvas. The mean period of the shaking motion with the round canvas was ~14 s, and the mean amplitude was 0.4 m as measured by peak event analysis and the global wavelet method. The bycatch of juvenile fish in 14 trials decreased by ~30% and by ~25% using a steady cod end for the total bycatch using a shaking cod end in the shrimp beam trawl, while the marketing catch was similar between steady and shaking cod ends. There was no difference in the body size of the shrimp or fish and species composition between the steady and shaking cod ends. Above results demonstrate a new method for bycatch reduction using an active stimulating device, although more detailed studies are needed.

• Journal of the Korea Institute of Military Science and Technology
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• v.22 no.6
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• pp.773-783
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• 2019

A numerical analysis of a turbulent flow with a 'large-eddy breakup device(LEBU)' was performed to investigate the influence of the device on the drag of underwater vehicle using commercial CFD code, FLUENT. In the present study, the vehicle drag was decomposed to skin-friction coefficient(C_f) and pressure coefficient(C_p). The variation of the vehicle C_f and C_p were observed with changing location of the device and Reynolds number. As a result, the device decreased the vehicle C_f because it suppressed the turbulent characteristics behind the device. The larger Reynolds number, the higher reduction effect when the device was placed in front part of, and near the vehicle. On the other hand, the device increased/decreased the vehicle C_p with increasing/decreasing turbulent kinetic energy at recirculating flow region behind the vehicle. The total drag change by the device was caused by C_p rather than C_f.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.12
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• pp.612-618
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• 2020

In recent years, the demand for external window cleaning has increased, but the process is a very dangerous manpower-dependent operation. In addition, it is difficult to clean at the desired frequency in a business that values cleanliness. Therefore, there is a need to automate this work. This paper presents the concept of a device that can be attached to a specific window and clean the window continuously. The economic feasibility of this device was analyzed. The estimated manufacturing cost of the equipment was approximately 10 million won, but the possible investment cost was at least 9.8 million won for five years of endurance and 103 million won for 10 years of endurance. Therefore, the expected savings well exceed the equipment cost, and it was evaluated as having economic feasibility. Since this study analyzed only quantitative indicators, the expected cost reduction due to a reduction in safety accidents, productivity improvement, construction time reduction, and quality improvement was not considered. Therefore, it is expected that the calculated economic feasibility will be more accurate if the cost reduction effect by the automation equipment is calculated by adding the expected values not considered in this study.

• Journal of Electrochemical Science and Technology
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• v.12 no.4
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• pp.406-414
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• 2021

Electrochemical devices are constructed for continuous syngas (CO + H₂) production with controlled selectivity between CO₂ and proton reduction reactions. The ratio of CO to H₂, or the faradaic efficiency toward CO generation, was mechanically manipulated by adjusting the space volume between the cathode and the polymer gas separator in the device. In particular, the area added between the cathode and the ion-conducting polymer using 0.5 M KHCO₃ catholyte regulated the solution acidity and proton reduction kinetics in the flow cell. The faradaic efficiency of CO production was controlled as a function of the distance between the polymer separator and cathode in addition to that manipulated by the electrode potential. Further, the electrochemical CO₂ reduction device using Au NPs presented a stable operation for more than 23 h at different H₂:CO production levels, demonstrating the functional stability of the flow cell utilizing the mechanical variable as an important operational factor.