• 한국재료학회지
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• 제13권2호
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• pp.133-136
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• 2003

Sn-2.5Cu alloy layers were deposited on the Alloy 42 lead-frame substrates by the electroplating method, and their microstructures, adhesion strength, and electrical resistivity were measured to evaluate the applicability of Sn-Cu alloy as a surface finishing material of electronic parts. The Sn-2.5Cu layers were electroplated in the granular form, and composed of pure Sn and Cu$_{6}$Sn$_{5}$ intermetallic compound. Surfaces of the electroplated Sn-2.5Cu layers were rather rough and also the thickness variance was large. The adhesion strength of the Sn-2.5Cu electroplated layers was highly comparable to that of the electroplated Cu alloy layer and the electrical conductivity was about 10 times higher than the pure Sn. After the 20$0^{\circ}C$ 30 min. annealing of the electroplated Sn-2.5Cu layers, the surface roughness was reduced, and adhesion strength and conductivity were improved. These results showed the Sn-Cu alloys can be used as an excellent surface finishing material.ial.

• 연구논문집
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• 통권22호
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• pp.151-160
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• 1992

The wear resistance of electroless Ni-P-X(X A1203, Diamond) composite coating layers was studied by Taber abrasion test technique. The wear resistance of composite coating layers was particularly relied upon the codeposited content, particle size and distribution of particles, and heat treatment of coating layers, as well as the electroless nickel plating bath employed. In this study, we lay emphasis on the wear resistance of electroless composite coating layers containing A1203 particles(1.2~Im, 6.7hIm, 11.5lIm, 20l1m) or diamond particles (1.5jim, 5gm). From the result of composite coating A1203 and diamond particles, the wear resistance of composite coating layers is as follows.

• 한국조리학회지
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• 제7권2호
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• pp.123-132
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• 2001

The contents of the pastry margarine were 30, 50, 70, 90 and 110% based on baker's %, and the layers of the dough were 18, 27, 36, 48 and 64 in danish pastry product In order to analyse on the effect of the theoretical one layer thickness of the pastry margarine, the volume, quality and sensory evaluation of the products have been carried out. The results as follows ; 1) Best volume was showed that the thickness of the dough was 5mm and the thickness of one layer was 0.039mm. 2) When the content of the pastry margarine was 30% and the thickness of one layer was 0.014mm(48 layers), when 50%, 0.039mm(27 layers), when 70%, 0.038(36 layers), when 90%, 0.034(48 layers) and when 110%, 0.039(48 layers), best volume was showed. 3) In the case when the content of pastry margarine was 70% and the thickness of one layer was 0.038mm(36 layers), as well as 110%, 0.039mm(48 layers), the taste were showed 5%, better than when 30%, 0.014(27 layers) in the sensory evaluation. Flavor and mouth feel was the same results. 4) For the best quality products, the content of the pastry margarine and the layers of the dough were very important.

• Computers and Concrete
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• 제26권5호
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• pp.377-384
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• 2020

A two-dimensional particle flow cod (PFC) is used to study the effect of missile impact on the concrete target. For this purpose firstly calibration of numerical model was performed so that tensile strength of numerical models and experimental sample were the same. Secondly, a concrete model was built. The number of concrete layers and the angle of concrete layers related to horizontal axis were changed. Their numbers were 1, 2, 3 and 4. The angles were 0°, 15°, 30°, 45°, 60°, 75° and 90°. A semi-circle missile was simulated at top of the concrete layers. Its velocity in opposite side of Y direction was 100 m/s. three measuring circles were situated at the below the missile in the model to receive the applied force. The load in the missile and measuring circles together with failure pattern were registered at the beginning of the impaction. The results show that concrete layers number and concrete layers angle have important effect on the failure load while the failure pattern was nearly constant in all of the models.

• Smart Structures and Systems
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• 제5권5호
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• pp.547-564
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• 2009

Based on the theory of piezoelasticity, an analytical solution for a typical multilayer piezoelectric composite cantilever is obtained by the Airy function method. The piezoelectric cantilever may consist of any number of layers. Moreover, the material and thickness for different layers may be different. The solution obtained in the present paper is concise and can be easily applied for the bending analysis of multilayer piezoelectric actuators considering the effect of bonding layers and electrodes. At last, a comprehensive parametric study is conducted to show the influence of electromechanical coupling (EMC), the number of piezoelectric layers, the elastic modulus of elastic layer and the thickness ratio on the bending behavior of actuators. Some interesting results for the design of multilayer piezoelectric actuators are presented.

• Journal of Biosystems Engineering
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• 제42권3호
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• pp.136-146
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• 2017

Purpose: This paper presents an appropriate wrapping method by analyzing the pressure distribution applied to a bale surface, along with the change in pressure according to an increase in the number of film layers in rice straw bales, which account for 74% of the total bulky feed supply in Korea. Methods: A model with the shape of an actual bale was fabricated to analyze the distribution of surface pressure in bale wrapping, and the pressure was measured. Experiments were conducted to analyze the pressure using eight different layer numbers (2, 4, 6, 8 10, 12, 14, and 16 layers) at five wrapping speeds (27, 29, 31, 33, and 35 rpm). Results: The maximum pressure applied to a circular bale by the film occurred at the center of the end of the bale, whereas the minimum pressure occurred at the center of the bale side. An extreme value ratio between the minimum and maximum pressures was distributed as 8.5-56.6%, which was improved with an increase in rotation speed. The an uneven pressure distribution occurred because the number of film overlaps was 8.24-times greater at the center of the bale's end than at the center of the ba le side. At a level 5 rotation speed, the minimum pressure was $P_{LV5-M1}=0.0625{\sigma}^2+36.173{\sigma}-36.753$ ($R^2=0.9845$) at $M_1$, and the maximum pressure was $P_{LV5-M6}=5.5552{\sigma}^2+41.05{\sigma}-39.071$ at $M_2$, revealing a correlation of $R^2=0.9983$. Conclusions: To replace four layers with six layers, 2-4 layers were added only to the side of the bale, and the minimum pressure at $M_1$ was then improved from that at four layers to that at six layers, and the amount of film consumed for 4-6 layers was reduced by 84.6%.

• Structural Engineering and Mechanics
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• 제68권5호
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• pp.537-547
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• 2018

This research presents the effect of anisotropy of the hollow disc mode under Brazilian test using PFC3D. The Brazilian tensile strength test was performed on the hollow disc specimens containing the bedding layers and then these specimens were numerically modeled by using the two dimensional discrete element code (PFC3D) to calibrate this computer code for the simulation of the cracks propagation and cracks coalescence in the anisotropic bedded rocks. The thickness of each layer within the specimens varied as 5 mm, 10 mm and 20 mm and the layers angles were changed as $0^{\circ}$, $25^{\circ}$, $50^{\circ}$, $75^{\circ}$ and $90^{\circ}$. The diameter of internal hole was taken as 15 mm and the loading rate during the testing process kept as 0.016 mm/s. It has been shown that for layers angles below $25^{\circ}$ the tensile cracks produce in between the layers and extend toward the model boundary till interact and break the specimen. The failure process of the specimen may enhance as the layer angle increases so that the Brazilian tensile strength reaches to its minimum value when the bedding layers is between $50^{\circ}$ and $75^{\circ}$ but its value reaches to maximum at a layer angle of $90^{\circ}$. The number of tensile cracks decreases as the layers thickness increases and with increasing the layers angle, less layer mobilize in the failure process.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2000년도 제1회 학술대회 논문집
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• pp.171-174
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• 2000

This study uses neon and xenon gas mixture discharges to determine the effects of the neon plasma emission on the characteristics of visible emission from the stimulation of the red, green, blue(RGB) phosphor layers in a surface-type alternate current plasma display panel(AC PDP). With a mixture of less than 2% xenon to neon, it is found that the luminance changes in the visible emission of the phosphor layers are similar to those of the neon plasma emission. In the range of xenon mix ratio from 2 to 5%, the luminance of the red, green, blue(RGB) phosphor layers decreases with a decrease in the neon plasma emission intensity. However, with a mixture of above 5% xenon to neon, the luminance of the red, green, blue(RGB) phosphor layers increases regardless of a decrease in the neon plasma emission intensity. Furthermore, the color purity of the red, green, blue(RGB) phosphor layers improve as the neon plasma emission intensity decreases. Accordingly, it is concluded that the optical properties of the phosphor layers, including color purity and luminance, depend on the neon plasma discharge emission as well as the visible emission from the stimulation of the phosphor layers.

• 한국분말재료학회지
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• 제26권5호
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• pp.421-431
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• 2019

In this study, the formation, microstructure, and wear properties of Colmonoy 88 (Ni-17W-15Cr-3B-4Si wt.%) + Stellite 1 (Co-32Cr-17W wt.%) coating layers fabricated by high-velocity oxygen fuel (HVOF) spraying are investigated. Colmonoy 88 and Stellite 1 powders were mixed at a ratio of 1:0 and 5:5 vol.%. HVOF sprayed self-fluxing composite coating layers were fabricated using the mixed powder feedstocks. The microstructures and wear properties of the composite coating layers are controlled via a high-frequency heat treatment. The two coating layers are composed of ${\gamma}-Ni$, $Ni_3B$, $W_2B$, and $Cr_{23}C_6$ phases. Co peaks are detected after the addition of Stellite 1 powder. Moreover, the WCrB2 hard phase is detected in all coating layers after the high-frequency heat treatment. Porosities were changed from 0.44% (Colmonoy 88) to 3.89% (Colmonoy 88 + ST#1) as the content of Stellite 1 powder increased. And porosity is denoted as 0.3% or less by inducing high-frequency heat treatment. The wear results confirm that the wear property significantly improves after the high-frequency heat treatment, because of the presence of well-controlled defects in the coating layers. The wear surfaces of the coated layers are observed and a wear mechanism for the Ni-based self-fluxing composite coating layers is proposed.

• 한국작물학회지
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• 제41권3호
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• pp.362-369
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• 1996

3년생 의성작약품종(faeornia lacrifora Pall.)을 1994년 2월에 수확하여 유피 및 거피상태로 처리한 후 상온음건법, 화력건조법, 증건법 및 냉동건조법으로 건조방법을 각각 달리하여 주 약용성분인 paeoniflorin함량 및 일반 화학성분을 조사한 결과는 다음과 같다. 1. 건물비율 50%까지의 건조일수는 거피상태 3$0^{\circ}C$ 화력건조가 동일온도의 유피상태보다 5일이 짧으며, 거피상태에서는 5$0^{\circ}C$ 화력건조법이 1.5일로 가장 빨랐고, 121$^{\circ}C$ 증건법은 8일로 가장 늦었다. 2. 상온음건 및 화력건조법의 경우 paeoniflorin 함량은 거피상태가 더 높았고, 반대로 증건법은 유피상태가 더 높았다. 화력건조법의 경우 건조온도가 높아짐에 따라 paeoniflorin 함량은 감소하였다. 3. 건조방법 중 3$0^{\circ}C$화력건조가 Paeoniflorin함량이 4.0%로 가장 높고, 건조일수가 단축되며, 색택 이 양호한 가장 적절한 건조법 이었다. 4. 화력건조시 건조온도가 높아짐에 따라 총당의 함량은 감소하고 전분은 증가하는 경향을 보였으며, 또 전분함량은 121$^{\circ}C$의 증건법을 제외한 모든 건조방법에서 거피상태보다 유피상태가 더 높았다. 5. 조단백질, 조섬유 및 조회분의 함량은 유피, 거피 및 건조방법에 따라 큰 차이가 없었다. 6. Paeoniflorin과 총당의 관계는 유피상태에서 정의 유의상관이, 그리고 paeoniflorin과 전분의 관계는 거피상태에서 부의 유의상관이 있었다.