• 한국전기전자재료학회논문지
• /
• 제11권11호
• /
• pp.954-962
• /
• 1998

Energy-trapped thickness vibrations of piezoelectric substrates are utilized in fabricating resonators and filters which have their operating frequencies in HF band. Normalized particle displacement distributions of the fundamental thickness shear vibration mode and overtone modes into the thickness direction in energy-trapped resonators and double-coupled filters were obtained by solving the wave equation and calculating the solved equations. These results show that as the number order of the harmonic mode in a energy-trapped resonator becomes larger, the degree of energy-trapping in the resonator increase, and if the conditions for energy-trapping become sufficiently weak, the energy-trapping effect of the harmonic mode which has the lower order disappears the earlier. Above simulation results were proved by the experiments.

• E2M - 전기 전자와 첨단 소재
• /
• 제9권9호
• /
• pp.954-963
• /
• 1996

Particle displacement distributions of the fundamental thickness shear vibration mode and overtone modes in an energy-trapped single resonator and an energy-trapped double acoustically coupled filter were calculated. The effects of the width of a pair of partial eletrodes and the magnitude of the plate back of the resonator on the particle displacement distributions of its symmetric vibration mode and anti-symmetric vibration mode were investigated. And the effects of the width of a pair of partial eletrodes, the width of the gap between two pairs of partial electrodes and the magnitude of the plate back of the filter on the particle displacement distributions of its symmetric vibration mode and anti-symmetric vibration mode were investigated.

• 한국전기전자재료학회논문지
• /
• 제16권7호
• /
• pp.593-598
• /
• 2003

In this paper, 3rd overtone mode energy-trapped filter using modified PbTiO$_3$ system ceramics was manufactured to apply for intermediate frequency(IF) SMD type fillet with splitted electrode and gap size. To investigate the effects of splitted electrode and gap size on filter characteristics of 3rd overtone mode energy-trapped filter, ceramic wafers were fabricated by etching splitted rectangular electrode size(b$\times$d) of b=0.4, 0.6, 0.8, 1mm, d=0.3, 0.4, 0.5, 0.6mm and gap size(c) c=0.2, 0.3, 0.4, 0.6mm, respectively. And then, SMD type ceramic filter were fabricated with the size of 3.7$\times$3.1$\textrm{mm}^2$. SMD type ceramic filter with the size of b=0.8mm, d=0.4mm and gap(c)=0.4mm, which showed insertion loss of 2.951dB, 3dB bandwidth of 54.7kHz and 20dB stop bandwidth of 129.27kHz, was suitable for IF bandpass filter application.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2002년도 추계학술대회 논문집 Vol.15
• /
• pp.83-86
• /
• 2002

In this paper, $3^{rd}$ overtone mode energy-trapped filter using modified $PbTiO_3$ system ceramics was manufactured to apply for intermediate frequency SMD-type filter with the variations of splitted electrode size. To investigate the effects of splitted electrode size on filter characteristics of $3^{rd}$ overtone mode energy-trapped filter, ceramic wafers were fabricated by etching splitted rectangular electrode size($b{\times}d$) of b=0.4, 0.6, 0.8, 1mm, d=0.3, 0.4, 0.5mm, respectively. And then, SMD-type ceramic filter were fabricated with the size of $3.7{\times}3.1mm$. With the variations of b size, insertion loss, 3dB bandwidth and 25dB stop bandwidth showed nearly constant value, but with the variations of d size, insertion loss, 3dB bandwidth, selectivity(shape factor) decreased.⨀؀က?⨀Ⴣ?⨀਀Ⴣ?⨀ꞻꎀ̀ကꮻꎀༀ뮻ꎀ᠀Ȁ햻ꎀĀힻꎀȀ?ꎀ̀?ꎀȀꎀĀꎀĀꎀĀꎀĀꎀЀȀꎀࠀꎀഀڼꎀഀᒼꎀ؀ᮼꎀ䈀ȀȀ悼ꎀऀ檼ꎀഀȀ禼ꎀഀ螼ꎀऀȀȀ鎼ꎀഀȀꊼꎀഀ낼ꎀࠀ즼ꎀԀ쾼ꎀ܀ힼꎀ

• Structural Engineering and Mechanics
• /
• 제21권1호
• /
• pp.53-66
• /
• 2005

When a large number of identical cylinders are placed in an array with equal separation distance, near-resonant phenomena may occur between cylinders at critical frequencies, and cause large wave forces on each element of the array. In this paper, 64 truncated circular cylinders arranged in 4 rows and 16 columns are considered to check occurrence of near-resonant phenomena and performance of theoretical predictions based on the potential flow. Experiments are conducted in head waves to measure the wave elevation along the longitudinal centerline of the model, and measured results are compared with numerical ones. Attention is focused on the spatial variation of the wave amplitude around the first near-trapped-mode frequency.

• 한국해안해양공학회지
• /
• 제4권1호
• /
• pp.1-9
• /
• 1992

해저계체 위를 지나는 미소진폭파의 변형을 계산하기 위해 고유함수 전개법과 진행파 근사법이 사용되었다. 흐름과 지형의 변화에 의해 억류되는 파낭의 특성과 파낭변형에 대한 evanescent mode의 영향을 조사하였다. 특히 3차원 뿐 아니라 2차원 파낭 만형을 도시하여 억류파낭의 특성을 분석하였다.

• 반도체디스플레이기술학회지
• /
• 제18권4호
• /
• pp.138-142
• /
• 2019

As the NAND flash memory goes to 3D vertical Silicon-Oxide-Nitride-Oxide-Silicon (SONOS) structure, the lateral charge migration can be critical in the reliability performance. Even more, with miniaturization of flash memory cell device, just a little movement of trapped charge can cause reliability problems. In this paper, we propose a method of predicting the trapped charge profile in the retention mode. Charge diffusivity in the charge trapping layer (Si₃N₄) was extracted experimentally, and the effect on the trapped charge profile was demonstrated by the simulation and experiment.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 1995년도 추계학술대회 논문집
• /
• pp.34-39
• /
• 1995

Particle displacement distributions of the fundamental mode and overtone modes in an energy-frapped single resonator and an energy-trapped double acoustically coupled filter using the thickness shear vibration were calculated. And the effects of the width of a pair of partial electrodes, the width of the gap between two pairs of partial electrodes and the magnitude of the plate back on the displacement distributions of the symmetric vibration mode and anti-symmetric vibration mode of the resonators and the filters were investigated.

• 한국음향학회지
• /
• 제1권1호
• /
• pp.37-44
• /
• 1982

In the mixed layer when the frequency approaches the cut-off frequency for the first mode of notmalmode theory, sound ceases to be trapped. Based on the data of surface sound velocities abtained during the period of 16 years in the Sea of Japan. A new cut-off frequency coefficient in the surface duct that will determine the miximum wave length for duct transimission of underwater sound has been calculated.

• 한국분무공학회지
• /
• 제25권3호
• /
• pp.103-110
• /
• 2020

In this study, the behavior of water droplet impacting on a thin horizontal wire was visualized by time-delay photography. The impact behavior modes, critical capture speed and trapped mass were analyzed by changing the droplet size, velocity, wire diameter and eccentricity ratio. As the Weber number increased, the hanging, merging, and splitting modes appeared sequentially for the case of central impact, and the hanging and non-splitting modes appeared for the case of off-center impact. The boundary We number of each mode was affected by the diameter ratio. The critical capture speed was affected much by the degree of eccentricity. For all diameter ratios, it was higher for the case of central impact than for off-center impact. The trapped mass was larger for the case of central impact than for off-center impact and it increased with the smaller We number and the larger diameter ratio.