• Polymer Science and Technology
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• v.15 no.3
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• pp.260-273
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• 2004

Layer-by-layer 자기조립방법 (self-assembly method) 이라고 불리는 담지자기조립방법 (dip self-assembly method)을 이용한 다층초박막은 다양한 전기적, 자기적 성질을 갖는 물질뿐만 아니라 DNA 또는 효소 (enzyme)같은 바이오 물질들을 기판의 크기나 형태에 관계없이 각각의 층에 나노미터 두께로 삽입시킬 수 있음에 따라서 초박막안에 우리가 원하는 특정 성질을 부여할 수 있다. (중략)

• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.352-354
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• 2005

As further Studies on 4th generation mobile telecommunication are progressed, the importance of a Cross-Layer is being increased. However, it has focused on coordination model only between MAC layer and PHY layer. It is necessary to expand into II' layer and upper layers. In this paper, we introduce a Cross-layer optimization which can be used to transmit video data with effect by managing resources among layers. It can gives further more adaptive method to solve QoS model problem than single layer.

• Journal of the Korean Ceramic Society
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• v.31 no.8
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• pp.874-878
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• 1994

To increase the anti-oxidation and anti-wear properties of graphite for the propellant-burning environment, SiC, Pt and Al2O3 multi-layer coatings were conducted succesisvely and the optimum condition was researched. The SiC layer was produced by pack cementation and SiC layer in thickness of 30 ${\mu}{\textrm}{m}$ coating was produced after coating for 6 hours. Pt layer was coated by sputtering, and the Al2O3 layer was coated by reactive sputtering. the thickness of Pt layer and Al2O3 layer was less than one-tenth of that of SiC layer. The pack coated specimens and multi-layer coated specimens were made using above conditions and test-fired. The test result showed that the wear rate of SiC layer is approximately 1/10 compared to that of uncoated graphite.

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.306-311
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• 2001

Effect of boundary layer thickness on the flow characteristics around a rectangular prism has been investigated by using a PIV(Particle Image Velocimetry) technique. Three different boundary layers(thick, medium and thin)were generated in the Atmospheric Boundary Layer Wind Tunnel at Pusan National University. The thick boundary layer having 670mm thickness was generated by using spires and roughness elements. The medium thickness of boundary layer$(\delta=270mm)$ was the natural turbulent boundary layer at the test section with fully long developing length(18m). The thin boundary layer with 36.5mm thickness was generated by on a smooth panel elevated 70cm from the wind tunnel floor. The Reynolds number based on the free stream velocity and the height of the model was $7.9{\times}10^3$. The mean velocity vector fields and turbulent kinetic energy distribution were measured and compared. The effect of boundary layer thickness is clearly observed not only in the length of separation bubble but also in the reattachment points. The thinner boundary layer thickness, the higher turbulent kinetic energy peak around the model roof. It is strongly recommended that the height ratio between model and approaching boundary layer thickness should be a major parameter.

• Proceedings of the KSME Conference
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• 2000.04b
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• pp.853-858
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• 2000

The working fluid from the combustor to the turbine stage of a gas turbine makes various boundary layer thickness. Since the inlet boundary layer thickness is one of the important factors that affect the turbine efficiency. It is necessary to investigate secondary flow and loss with various boundary layer thickness conditions. In the present study, the effect of various inlet boundary layer thickness on secondary flow and loss and the proper height of the boundary layer fences for various boundary layer thickness were investigated. Measurements of secondary flow velocity and total pressure loss within and downstream of the passage were taken under 5 boundary layer thickness conditions, 16, 36, 52, 69, 110mm. It was found that total pressure loss and secondary flow areas were increased with increase of thickness but they were maintained almost at the same position. At the fellowing research about the boundary layer fences, 1/6, 1/3, 1/2 of each inlet boundary layer thickness and 12mm were used as the fence heights. As a result, it was observed that the proper height of the fences was generally constant since the passage vortex remained almost at the same position. Therefore once the geometry of a cascade is decided, the location of the Passage vortex and the proper fence height are appeared to be determined at the same time. When the inlet boundary layer thickness is relatively small, the loss caused by the proper fence becomes bigger than endwall loss so that it dominates secondary loss. In these cases the proper fence hight is decided not by the cascade geometry but by the inlet boundary layer thickness as previous investigations.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.12
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• pp.1356-1361
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• 2004

High temperature superconducting coated conductor has a structure of ///. The buffer layer consists of multi-layer, this study reports the deposition method and optimal deposition conditions of YSZ(Yttria-stabilized zirconia) layer which plays a important part in preventing the elements of substrate from diffusing into the superconducting layer. YSZ layer was deposited by DC reactive sputtering technique using water vapor for oxidizing deposited elements on substrate. To investigate optimal thickness of YSZ film, four YSZ/CeO$_2$/Ni samples with different YSZ thickness(130 nm, 260 nm, 390 nm, and 650 nm) were prepared. The SEM image showed that the surface of YSZ layer was getting to be rougher as YSZ layer was getting thicker and the growth mode of YSZ layer was columnar grain growth. After CeO$_2$ layer was deposited with the same thickness of 18.3 nm on each four samples, YBCO layer was deposited by PLD method with the thickness of 300 nm. The critical currents of four samples were 0, 6 A, 7.5 A, and 5 A respectively. This shows that as YSZ layer is getting thicker, YSZ layer plays a good role as a diffusion barrier but the surface of YSZ layer is getting rougher.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.28B no.11
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• pp.852-858
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• 1991

An adaptive hierarchical classifier(AHCL) for Korean character recognition using a neural net is designed. This classifier has two neural nets: USACL (Unsupervised Adaptive Classifier) and SACL (Supervised Adaptive Classifier). USACL has the input layer and the output layer. The input layer and the output layer are fully connected. The nodes in the output layer are generated by the unsupervised and nearest neighbor learning rule during learning. SACL has the input layer, the hidden layer and the output layer. The input layer and the hidden layer arefully connected, and the hidden layer and the output layer are partially connected. The nodes in the SACL are generated by the supervised and nearest neighbor learning rule during learning. USACL has pre-attentive effect, which perform partial search instead of full search during SACL classification to enhance processing speed. The input of USACL and SACL is a directional edge feature with a directional receptive field. In order to test the performance of the AHCL, various multi-font printed Hangul characters are used in learning and testing, and its processing its speed and and classification rate are compared with the conventional LVQ(Learning Vector Quantizer) which has the nearest neighbor learning rule.

• Journal of Environmental Science International
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• v.10 no.6
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• pp.417-422
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• 2001

The vertical structure of atmosphere was observed In investigate the variation of surface ozone concentration by vertical downward mixing of residual ozone in the atmospheric boundary layer at the Busan coastal area. Airsonde and pilot balloon measurements were made at Gamcheondong and the Kimhae airport for April 26~27, 1996. The vertical potential of potential temperature showed a residual layer between 510m and 1800m from 2100LST April 26 to 0900LST April 27. The downward mixing of ozone in the residual layer of the atmospheric boundary layer was confirmed from vertical profile of mixing ratio near 600m in the morning. The thickness of the sea breeze layer was 900m at 1500LST April 26. Thereafter, it become to be lowered with time A low level jet was measured near 900m at 0300LST on April 27 from a pibal measurement. Early morning sharp increase of surface ozone concentration at the Busan coastal area was caused by vertical downward mixing of ozone concentration rather than by photochemical reaction In the atmospheric boundary layer.

• Bulletin of the Korean Chemical Society
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• v.30 no.9
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• pp.2165-2168
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• 2009

• Polymer Science and Technology
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• v.24 no.5
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• pp.488-500
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• 2013