• 공업화학
• /
• 제28권4호
• /
• pp.427-431
• /
• 2017

최근 공동주택이 증가함에 따라 층간소음문제가 증가하고 있다. 이로 인해 더 효과적인 층간소음저감 시스템이 요구되고 있다. 향후 고층빌딩이 더 많이 건설될 것이므로 이런 시스템은 시장에서 더욱 수요가 요구되어지는 중요한 기술이다. 본 연구에서는 폐고무를 이용하여 신규 바닥 소음 저감 판넬을 설계하고 제작하였다. 실험실 및 실제 필드조건에서 소음 저감을 조사하였다. Field test 결과 경량 및 중량충격음 레벨이 각각 52, 48 dB로 우수한 결과를 보였다. 기존 구조 대비하여 22~42 mm의 두께 저감을 할 수 있었다.

• 센서학회지
• /
• 제30권2호
• /
• pp.119-124
• /
• 2021

Isolation and separation of biological nanoparticles, such as cells and extracellular vesicles, are important techniques for their characterization. Dielectrophoresis (DEP) based on microfluidic chips is an effective method to isolate and separate the nanoparticles. However, the electrodes of the DEP chips are electrolyzed by the electrical signals applied to the nanoparticles. Thus, the isolation/separation efficiency of the nanoparticles is reduced considerably. Through this study, we developed a microfluidic DEP chip for reliable isolation/ separation of nanoparticles and developed a passivation technique for the protection of the DEP chip electrodes. The electrode passivation process was designed using a hydrogel and the stability of the hydrogel passivation layer was verified. The fabricated DEP chip and the proposed passivation technique were used for the collection and dispersion of the fluorescent polystyrene nanoparticles. The proposed chip and the technique for isolation and separation of nanoparticles can be leveraged in various bioelectronic applications.

• Journal of Power Electronics
• /
• 제14권5호
• /
• pp.967-979
• /
• 2014

This paper focuses on speed and current sensor fault detection and isolation (FDI) for induction motor (IM) drives. A new, accurate and high-efficiency FDI approach is proposed so that a system can continue operating with good performance even in the presence of speed sensor faults, current sensor faults or both. The proposed three paralleled adaptive observers are capable of current sensor fault detection and localization. By using observers, the rotor flux and rotor speed can be estimated which allows the system to run under the speed sensorless vector control mode when a speed sensor fault occurs. In order to detect speed sensor faults, a threshold-based scheme is proposed. To verify the feasibility and effectiveness of the proposed FDI strategy, experiments are carried out under different conditions based on a dSPACE DS1104 induction motor drive platform.

• Smart Structures and Systems
• /
• 제16권4호
• /
• pp.701-723
• /
• 2015

Friction isolators are one of the most important types of bearings used to mitigate damages of earthquakes. The adaptive behavior of these isolators allows them to achieve multiple levels of performances and predictable seismic behavior during different earthquake hazard levels. There are three main types of friction isolators. The first generation with one sliding surface is known as Friction Pendulum System (FPS) isolators. The double concave friction pendulum (DCFP) with two sliding surfaces is an advanced form of FPS, and the third one, with fully adaptive behavior, is named as triple concave friction pendulum (TCFP). The current study has been conducted to investigate and compare seismic responses of these three types of isolators. The structure is idealized as a two-dimensional single degree of freedom (SDOF) resting on isolators. The coupled differential equations of motion are derived and solved using state space formulation. Seismic responses of isolated structures using each one of these isolators are investigated under seven near fault earthquake motions. The peak values of bearing displacement and base shear are studied employing the variation of essential parameters such as superstructure period, effective isolation period and effective damping of isolator. The results demonstrate a more efficient seismic behavior of TCFP isolator comparing to the other types of isolators. This efficiency depends on the selected effective isolation period as well as effective isolation damping. The investigation shows that increasing the effective isolation period or decreasing the effective isolation damping improves the seismic behavior of TCFP compared to the other isolators. The maximum difference in seismic responses, the base shear and the bearing displacement, for the TCFP isolator are calculated 26.8 and 13.4 percent less than the DCFP and FPS in effective isolation damping equal to10%, respectively.

• Structural Engineering and Mechanics
• /
• 제51권2호
• /
• pp.277-297
• /
• 2014

Since the isolation bearings undergo large displacements in base-isolated structures, impact with adjacent structures is inevitable. Therefore, in this investigation, the effect of impact on seismic response of isolated structures mounted on double concave friction pendulum (DCFP) bearings subjected to near field ground motions is considered. A non-linear viscoelastic model of collision is used to simulate structural pounding more accurately. 2-, 4- and 8-story base-isolated buildings adjacent to fixed-base structures are modeled and the coupled differential equations of motion related to these isolated systems are solved in the MATLAB environment using the SIMULINK toolbox. The variation of seismic responses such as base shear, displacement in the isolation system and superstructure (top floor) is computed to study the impact condition. Also, the effects of variation of system parameters: isolation period, superstructure period, size of seismic gap between two structures, radius of curvature of the sliding surface and friction coefficient of isolator are contemplated in this study. It is concluded that the normalized base shear, bearing and top floor displacement increase due to impact with adjacent structure. When the distance between two structures decreases, the base shear and displacement increase comparing to no impact condition. Besides, the increase in friction coefficient difference also causes the normalized base shear and displacement in isolation system and superstructure increase in comparison with bi-linear hysteretic behavior of base isolation system. Totally, the comparison of results indicates that the changes in values of friction coefficient have more significant effects on 2-story building than 4- and 8-story buildings.

• 한국군사과학기술학회지
• /
• 제2권1호
• /
• pp.82-89
• /
• 1999

In this article, the performances of acoustic enclosure with double resilient mount system which was designed by ADD to reduce the radiated noise by main noise source of ships, was tested and evaluated. From test results, it was verified that the acoustic performances of acoustic enclosure satisfied the requirements; vibration isolation level at 1st stage mount system of 15 ㏈ and airborne noise reduction level of 20 ㏈ in broad band.

• 한국어업기술학회:학술대회논문집
• /
• 한국어업기술학회 2000년도 춘계수산관련학회 공동학술대회발표요지집
• /
• pp.151-152
• /
• 2000

During in door or outdoor mass culture, Porphyra have been easily contaminated with bacteria, protozoa and microalgal species. Several axenic treatments for Porphyra thalli have been published (Polne-Fuller and Gibo 1984; Chen and McCracken 1993), but axenic techniques for neutral spores and conchocelis we not developed. In this work we describe the procedure for axenic isolation of neutral spores and conchocelis of Porphyra yezoensis (omitted)

• 한국균학회지
• /
• 제26권2호통권85호
• /
• pp.275-280
• /
• 1998

장수버섯(Fomitella fraxinea)의 원형질체 분리와 재생에 영향을 미치는 요인을 조사하고자 본 연구를 수행하였다. 세포벽 분해 효소 종류별 원형질체 분리 시험을 수행한 결과 장수버섯 ASI 17001은 Novozym 234+Cellulase onozuka R-10+${\beta}-Glucuronidase$를 혼합하여 처리하였을 때 원형질체 분리율이 $8.9{\times}10^4/ml$로 가장 높았다. 원형질체 분리시 사용하는 삼투압 조절제로는 0.6 M sucrose가 가장 양호하였으며, 처리시간은 3시간이 가장 양호하였다. 원형질체 재생율은 0.6 M sorbitol에서 0.02%로 다른 조절제에 비하여 양호한 결과를 나타내었으나 KCl는 전혀 재생이 되지 않았다.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2007년도 추계학술대회 논문집
• /
• pp.115-117
• /
• 2007

This paper is analyzed for DC-DC chopper performance of high efficiency added in electric isolation. The general converters of high efficiency are made that the power loss of the used switching devices is minimized. To achieve high efficiency system, the proposed chopper is constructed by using a partial resonant circuit. The control switches using in the chopper are operated with soft switching for a partial resonant method. The control switches are operated without increasing their voltage and current stresses by the soft switching technology. The result is that the switching loss is very low and the efficiency of chopper is high. And the proposed chopper is added in a electric isolation. When the power conversion system is required to electric isolation, the proposed chopper is adopted with system development of high efficiency. The soft switching operation and the system efficiency of the proposed chopper is verified by digital simulation and experimental results.

• JSTS:Journal of Semiconductor Technology and Science
• /
• 제13권4호
• /
• pp.402-409
• /
• 2013

An innovative application of voltage-contrast (VC) inspection allowed inline detection of NMOS leakage in dense SRAM cells is presented. Cell sizes of SRAM are continual to do the shrinkage with bit density promotion as semiconductor technology advanced, but the resulting challenges include not only development of smaller-scale devices, but also intra-devices isolation. The NMOS leakage caused by the underneath n+/P-well shorted to the adjacent PMOS/N-well was inspected by the proposed electron-beam (e-beam) scan in which VC images were compared during the in-line process step of post contact tungsten (W) CMP (Chemical Mechanical Planarization) instead of end-of-line electrical test, which has a long response time. A series of experiments based on the mechanism for improving the intra-well isolation was performed and verified by the inline VC inspection. An optimal process-integration condition involved to the tradeoff between the implant dosage and photo CD was carried out.