• Proceedings of the Korean Vacuum Society Conference
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• 한국진공학회 2010년도 제39회 하계학술대회 초록집
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• pp.255-255
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• 2010

Recently, nonvolatile memories (NVM) of various types have been researched to improve the electrical performance such as program/erase voltages, speed and retention times. Also, the charge trap memory is a strong candidate to realize the ultra dense 20-nm scale NVM. Furthermore, the high charge efficiency and the thermal stability of SiC nanocrystals NVM with single $SiO_2$ tunnel barrier have been reported. [1-2] In this study, the SiC charge trap NVM was fabricated and electrical properties were characterized. The 100-nm thick Poly-Si layer was deposited to confined source/drain region by using low-pressure chemical vapor deposition (LP-CVD). After etching and lithography process for fabricate the gate region, the $Si_3N_4/SiO_2/Si_3N_4$ (NON) and $SiO_2/Si_3N_4/SiO_2$ (ONO) barrier engineered tunnel layer were deposited by using LP-CVD. The equivalent oxide thickness of NON and ONO tunnel layer are 5.2 nm and 5.6 nm, respectively. By using ultra-high vacuum magnetron sputtering with base pressure 3x10-10 Torr, the 2-nm SiC and 20-nm $SiO_2$ were successively deposited on ONO and NON tunnel layers. Finally, after deposited 200-nm thick Al layer, the source, drain and gate areas were defined by using reactive-ion etching and photolithography. The lengths of squire gate are $2\;{\mu}m$, $5\;{\mu}m$ and $10\;{\mu}m$. The electrical properties of devices were measured by using a HP 4156A precision semiconductor parameter analyzer, E4980A LCR capacitor meter and an Agilent 81104A pulse pattern generator system. The electrical characteristics such as the memory effect, program/erase speeds, operation voltages, and retention time of SiC charge trap memory device with barrier engineered tunnel layer will be discussed.

• Journal of the Society of Naval Architects of Korea
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• 제58권3호
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• pp.137-143
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• 2021

In this study, the fracture strength of Flexible Secondary Barrier (FSB) composites was standardized by conducting a distribution analysis of the fracture probability, considering that the fracture strength of FSB composites such as glass fiber reinforced composites is relatively large. As the mechanical performance of FSB composites varies with the fiber direction, 20 replicate uniaxial tensile tests were performed for different temperatures ranging from the ambient to cryogenic conditions, considering the actual operating environment of liquefied natural gas. For the probability statistical analysis, the Weibull distribution analysis derived from the weakest link theory was used, considering the large variance in the fracture strength and brittle fracture behavior. The results of the Weibull distribution analysis were used to calculate the standard fracture strength of the FSB composites for different fiber directions. The findings can help ensure the reliability of the FSB mechanical properties in different fiber directions in the design of the secondary barrier and structural analyses.

• Journal of KIBIM
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• 제10권4호
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• pp.1-10
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• 2020

While the importance of barrier-free and fire evacuation design is highlighted in architectural design education, systemic analysis, and examination on such performances are still challenging due to methodological lacks. The present study investigates the effectiveness of BIM-based human behavior simulation for architecture major students' analytical examinations to promote barrier-free and fire evacuation performances. To achieve such an aim, quasi-experiments were conducted, which compare 50 students' analysis and examination scores according to the use and non-use of the simulation, and the data were collected via participants' survey and interview. As a result, T-Test and MANOVA analyses indicate that, compared with its non-use counterpart, the use of human behavior simulation better facilitates the students' (1) examination of the physical properties and dimensions for the disabled's accessibility and evacuation, (2) understanding of the bodily capacity and handicap of the disabled, (3) examination on the spatial layouts and locations of exits, (4) understanding on evacuees' urgent behaviors, and (5) responsibility as an architect. Based on previous studies, the reasons of statistical results are interpreted as the explicit observation and analytical measures of multiple numbers of virtual-evacuees and direct-experience from body range of the disabled responding to the populated occupants as what they face in authentic reality.

• Journal of the Semiconductor & Display Technology
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• 제21권2호
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• pp.11-14
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• 2022

In this work, we evaluated the Al₂O₃ film, which was deposited by atomic layer deposition, degraded by exposure to harsh environments. The Al₂O₃ films deposited by atomic layer deposition have long been used as a gas diffusion barrier that satisfies barrier requirements for device reliability. To investigate the barrier and mechanical performance of the Al₂O₃ film with increasing temperature and relative humidity, the properties of the degraded Al₂O₃ film exposed to the harsh environment were evaluated using electrical calcium test and tensile test. As a result, the water vapor transmission rate of Al₂O₃ films stored in harsh environments has fallen to a level that is difficult to utilize as a barrier film. Through water vapor transmission rate measurements, it can be seen that the water vapor transmission rate changes can be significant, and the environment-induced degradation is fatal to the Al₂O₃ thin films. In addition, the surface roughness and porosity of the degraded Al₂O₃ are significantly increased as the environment becomes severer. the degradation of elongation is caused by the stress concentration at valleys of rough surface and pores generated by the harsh environment. Becaused the harsh envronment-induced degradation convert amorphous Al₂O₃ to crystalline structure, these encapsulation properties of the Al₂O₃ film was easily degraded.

• Animal Bioscience
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• 제35권6호
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• pp.858-868
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• 2022

Objective: This study was conducted to evaluate the effects of dietary yeast hydrolysate (YH) supplementation on intestinal morphology, barrier, and anti-inflammatory functions of broilers. Methods: A total of 320 one day old male broilers were randomly allocated into four groups with eight replicates of ten broilers each. The broilers were supplemented with a basal diet (the control group) or basal diets adding 50, 100, 150 mg/kg YH, respectively. This trial lasted for 42 days. The orthogonal polynomial contrasts were used to determine the linear and quadratic effects of increasing levels of YH. Results: In our previous research, supplementing YH improved growth performance by enhancing body weight gain but decreased feed-to-gain ratio. In this study, compared with the control group, dietary YH addition linearly and quadratically decreased serum diamine oxidase activity (p<0.05). Additionally, supplementing YH linearly and/or quadratically decreased jejunal crypt depth (CD), tumor necrosis factor-alpha (TNF-α) concentration as well as mucin 2, interleukin-6 (IL-6), IL-1β, TNF-α, nuclear factor kappa B, and myeloid differentiation factor 88 gene expression levels (p<0.05). Whereas the jejunal villus height (VH), VH/CD, IL-10 concentration as well as zonula occludens-1 and IL-10 gene expression levels were linearly and/or quadratically increased by YH supplementation (p<0.05). Conclusion: Dietary YH supplementation improved intestinal morphology, barrier and anti-inflammatory functions while decreased intestinal permeability of broilers, which might be related with altering pertinent genes expression. This study provides evidence of YH as a promising feed additive for broilers.

• Journal of the Korean Society of Industry Convergence
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• 제26권3호
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• pp.499-507
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• 2023

The core of the liquefied natural gas (LNG) carrier cargo containment system (CCS) is to store and transport LNG safely under temperatures below -163 degrees Celsius. The secondary barrier of the LNG CCS is adopted to prevent LNG leakage from CCS to the ship's hull structure. Recently, as the size of the LNG CCS increases, various studies have been conducted on the applied temperature and load ranges. The present study investigates the working condition-dependent bonding strength of the PU15 adhesives of the secondary barrier. In addition, the mechanical performance is analyzed at a cryogenic temperature of -170 degrees Celsius, and the failure surface and failure mode are investigated depending on the working condition of the bonded process. Even though the RSB and FSB-based fracture mode was confirmed, the results showed that all the tested scenarios satisfied the minimum requirement of the regulation.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.429-430
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• 2002

In this study, three kinds of brake: discs including two coated brake discs and one steel disc were tested under the same experimental conditions on a reduced scale braking test bench. Plasma spray coating technique was used to coat ceramic powder on the discs. In the test, four commercial sintered brake pads were coupled with discs. Ceramic coated discs have shown good stability in friction coefficient at high speed and high energy braking conditions. However, ceramic coated discs caused more wear loss of pad mass than the steel disc. It was shown that thermal barrier effect in ceramic coated discs adjusted the thermal partition between pad and disc. Steel disc showed fluctuating friction coefficient at high speed but less wear loss of pad mass than ceramic coated discs.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 한국전기전자재료학회 1995년도 춘계학술대회 논문집
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• pp.47-49
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• 1995

We report the spectroscopic properties of column-III nitrifies of GaN, GaInN, and AlGaN. The column-III nitride semiconductors are promising materials to realize the current-injection-type blue-and ultraviolet (UV)-light-emitting devices with high performance. To acheive the lasing with low threshold, the devices are must constructed to double heterostructure by succesive epitaxial growth technique, and we must confine the carriers in the potential barrier and optical confinement in wave guide between barrier and active layers has different refractive index. The refractive index of column-III nitride semiconductors, however, are rarely reported. The measured refractive index was 2.9, and the observed characteristic peak near the enrgy gap was analysed using a dielectric function and may due to excitonic contribution.

• Proceedings of the KIEE Conference
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• 대한전기학회 2006년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.158-160
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• 2006

The structure of interior permanent magnet type brushless DC motor (IPM type BLDC motor) has high saliency ratios that produce additional reluctance torque. But this structure has a significant cogging torque that may cause acoustic noise and vibration. In this paper describes an optimization of flux barrier in order to reduce cogging torque and torque ripple in IPM type BLDC motor using the Taguchi methods. The optimal design consider- ed noises such as manufacturing tolerances of permanent magnet size. So, optimal design ensures that torque performance is insensitive to noise.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.956-959
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• 2007

기존 투명방음판용 알루미늄 프레임의 구조적 단점을 보완할 수 있는 강재-FRP(Fiber Reinforced Plastic) 합성단면 구조재를 개발하였으며, 아울러 조립이 간편하고 외부 충격에 의해 쉽게 분리가 되지 않는 삽입형 수평재-수직재 코너연결부 상세를 개발하였다. 개발된 강재-FRP 합성단면 구조재와 코너연결재를 결합하여 프레임을 형성하고 그 사이에 투명패널을 삽입함으로써 길이 4m, 높이 1m 투명방음판 시작품을 완성하였으며, 이렇게 완성된 투명방음판 시작품을 대상으로 KS 4770-1 구조성능 평가시험을 수행하였다. 한국도로공사 교량부 시험하중에 대해 설계된 강재-FRP 합성단면 프레임 투명방음판의 구조성능 평가결과, FRP 의 추가적인 구조강성 증가 효과로 인해 한국도로공사 교량부 시험하중을 약간 상회하는 KS 2 호 등급시험하중까지도 만족시키고 있음을 확인할 수 있었다.