• Wind and Structures
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• 제38권6호
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• pp.411-425
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• 2024

To investigate the optimal aerodynamic parameters of wind barriers for the T-beam of high-speed railway (HSR) bridge and the wind field of the wind barrier-train-bridge system, the three-component forces of the system and the wind pressure on the vehicle surface were tested and analyzed through the sectional model wind test. The effects of wind velocity, with/without wind barrier, the height of wind barrier, and the air permeability of the wind barrier on the aerodynamic characteristics of the train-bridge system are discussed. Additionally, a CFD numerical model is constructed to evaluate the wind environment of the bridge surface with/without the wind barrier, and the impact of wind barrier on the running safety of vehicles are analyzed. Comprehensively considering the running safety of the train and the wind-resistant stability of the bridge, it is more appropriate to set the wind barrier height H as 3.5 m and the porosity 𝛽 as 30% respectively.

• 전자공학회논문지A
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• 제30A권7호
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• pp.47-59
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• 1993

16M DRAM 용 Al/Si contact 의 열적안정성을 개선하기 위하여 "stuffed" TiN/Ti diffusion barrier를 사용하였다. Diffusion barrier 로서의 특성을 개선하기 위한 Al 증착전 TiN/Ti barrier metal의 열처리 과정중 barrier metal의 두께, 열처리온도, 분위기 등을 변화시켰다. 질소분위기하에서 450도에서 TiN(900A)/Ti(300A) 박막을 열처리 하여 "stuffed" barrier metal을 형성 시켰을 경우 Al 원자의 TiN층으로의 확산의 600도에서 후속열처리한 경우 일어났으나, 700도까지도 Al-spike를 관찰할 수 없었다. 그러나 "stuffed" barrier metal을 550도에서 형성한 경우에는 600도의 후속열처리온도에서 Al이 Si 기판으로 침투했음을 관찰하였다. 박막의 두께를 얇게한 경우, 600도의 후속 열처리에서 Al-spike가 형성되었음을 확인하였다.

• Wind and Structures
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• 제20권4호
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• pp.509-525
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• 2015

A three-dimensional aerodynamic model and a vehicle dynamics model are established to investigate the effect of noise barrier on the dynamic performance of a high-speed train running on an embankment in crosswind in this paper. Based on the developed model, flow structures around the train with and without noise barrier are compared. Effect of the noise barrier height on the train dynamic performance is studied. Then, comparisons between the dynamic performance indexes of the train running on the windward track and on the leeward track are made. The calculated results show that the noise barrier has significant effects on the structure of the flow field around the train in crosswind and thus on the dynamic performance of the high-speed train. The dynamic performance of the train on the windward track is better than that on the leeward track. In addition, various heights of the noise barrier will have different effects on the train dynamic performance. The dynamic performance indexes keep decreasing with the increase of the noise barrier height before the height reaches a certain value, while these indexes have an inverse trend when the height is above this value. These results suggest that optimization on the noise barrier height is possible and demonstrate that the designed noise barrier height of the existing China Railway High-speed line analysed in this article is reasonable from the view point of the flow field structure and train dynamic performance although the noise barrier is always designed based on the noise-related standard.

• Asian Journal of Atmospheric Environment
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• 제8권2호
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• pp.81-88
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• 2014

Noise-barriers on both sides of the roadway (hereafter referred to as double noise-barriers), are a common feature along roads in Korea, and these are expected to have important effects on the near-road air pollution dispersion of vehicle emissions. This study evaluated the double noise-barrier impact on near-road air pollution dispersion, using a FLUENT computational fluid dynamics (CFD) model. The realizable k-${\varepsilon}$ model in FLUENT CFD code was used to simulate vehicle air pollutant dispersion, in around 11 cases of double noise-barriers. The simulated concentration profiles and surface concentrations under no barrier cases were compared with the experimental results. The results of the simulated flows show the following three regimes in this study: isolated roughness (H/W=0.05), wake interface (H/W=0.1), and skimming flow (H/W>0.15). The results also show that the normalized average concentrations at surface (z=1 m) between the barriers increase with increasing double noise-barrier height; however, normalized average concentrations at the top position between the barriers decrease with increasing barrier height. It was found that the double noise-barrier decreases normalized average concentrations of leeward positions, ranging from 0.8 (H/W=0.1, wake interface) to 0.1 (H/W=0.5, skimming flow) times lower than that of the no barrier case, at 10 x/h downwind position; and ranging from 1.0 (H/W=0.1) to 0.4 (H/W=0.5) times lower than that of the no barrier case, at 60 x/h downwind position.

• 공업화학
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• 제10권8호
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• pp.1114-1118
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• 1999

플라즈마 디스플레이 패널(PDP)의 격벽(barrier rib)은 일정한 선폭과 높이를 가져 균일한 방전 공간을 제공하고, 인접한 셀 간의 전기적, 광학적 혼선(crosstalk)을 방지하기 위해 PDP의 하부 유리 기판 패널에 들어가는 구조물이다. 본 연구에서는 사진식각(photolithography)법으로 격벽을 형성하는데 필요한 감광성 격벽 페이스트가 제조되었다. 페이스트는 바인더 고분자인 에틸셀룰로오즈를 BC/BCA = 30/70 wt %인 혼합 용매에 15 wt %로 용해한 다음 관능성 단량체로서TPGDA/PETA = 50/50 wt % 혼합물, 광개시제로서 Irgacur 651 및 격벽 분말을 도입한 다음 전체를 균일하게 분산시켜 제조하였다. 감광성 격벽 페이스트의 각 성분, 조성 및 공정을 최적화하여 소성 후 높이 약 $100{\mu}m$ 에 이르는 PDP용 격벽을 고해상도로 사진식각법으로 얻을 수 있었다.

• 대한한방소아과학회지
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• 제36권1호
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• pp.57-64
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• 2022

Objectives The purpose of this study is to confirm the regulate effect of T helper (Th) 2 differentiation that Sabaek-san extract may produce to improves skin lipid barrier damage. Methods Four-weeks-old NC/Nga mice were divided into four groups: control group (Ctrl, n=10), lipid barrier eliminated group (LBE, n=10), Dexamethasone treatment after lipid barrier elimination group (DXT, n=10), and Sabaek-san extract treatment group after lipid barrier elimination (SBT, n=10). Sabaek-san extract was administered for 3 d after removal of the skin fat barrier in SBT group. Then, we identified changes in external symptoms of the skin, factors affecting skin barrier such as potential of hydrogen (pH), filaggrin, transepidermal water loss (TEWL) and Th2 differentiation factors like Interleukin (IL)-4, Kallikrein Related Peptidase 7 (KLK7), and protease activated receptor 2 (PAR-2) through our immunohistochemistry. Results After lipid barrier elimination, the reduction of morphological skin inflammations was less in SBT group than in LBE and DXT group. Also, pH and TEWL were significantly decreased with SBT group. However, filaggrin was significantly increased in SBT group compared to LBE, DXT, and Ctrl group. All kinds of Th2 differentiation factors (IL-4, KLK7 and PAR-2) were also decreased in SBT compared to the LBE and DXT. Conclusions As a result of this study, SBT administration decreased pH, TEWL, and increased filaggrin, thus participating in recovering damaged skin barrier. Since Th2 differentiation factors were decreased as well, SBT's regulatory effect in sequential immune reactions may be a possible explanation of how it enhances recovery of the damaged lipid barrier.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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• pp.749-754
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• 2002

This paper investigates the insertion loss of nosie barrier with a interference device. The efficiency of the conventional interference-type noise barrier depends on specific frequency. Thus this study is performed to improve the efficiency of the nosie barrier in the range of broadband frequency, by changing the shape of interference device and adding the channel with various depths. The boundary element method (BEM) is used to predict the insertion loss of noise barrier. Two-dimensional boundary element model is created to simulate the performance of long barrier with a line source.

• The Korean Journal of Ceramics
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• 제4권1호
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• pp.37-42
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• 1998

The barrier heights and carrier densities of ZnO varistors with various compositions were estimated using C-V, J-V and $\rho$-T relations. The barrier heights obtained from C-V and J-V plots were 0.73~5.98 eV and 0.25~2.70 eV, respectively. The carrier densities estimated from C-V plots were ~$10^{18}cm^{-3}$. Acceptable values of the barrier heights and the carrier densities were obtained from $\rho$-1/T curves and the capacitances at zero bias; 0.6~0.8 eV for the barrier heights and ~$10^{17}cm^{-3}$ for carrier densities. Addition of cobalt increased the barrier height and the carrier density, while chromium slightly lowered both of them.

• 소음진동
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• 제9권3호
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• pp.466-471
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• 1999

The prediction methods of diffraction field in barrier has beenreported much about the infinite length barrier and it is very few work that reasonable sound source was used in experiment. This study, however, has worked about the several model barrier with acoustic scale model experiment. In the case of scale model experiment, it is difficult to use the kind of source with sufficiently characteristics. A spark discharge sound source with the high repeatability, broad band spectra, small size and omnidirectivity has veen used for the prediction of diffraction field. Several model barriers with different length on the ground were considered for the experiment and compared with the the results calculated by the approximation.

• 소음진동
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• 제6권2호
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• pp.245-251
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• 1996

This study is to suggest the improved noise barrier which is harmonized with surrounding landscape and maintained the similar reduction of reflected sound and diffraction effects in comparison with the aluminum noise barrier of absorbing type which is formed a great majority in Korea. In this study the two improved models of noise barrier(Diffuse and Disperse type) were designed and compared with the noise barriers of absorbing type in the acoustics performance (the reduction of reflected sound and diffraction effects) through the field and full-scale experimental measurement. As these two models have the same acoustic performance as the noise barrier of aluminum absorbing type, it is suggested that these models can be applied to the improved noise barrier as an alteration of aluminum absorbing type barrier.