• Title/Summary/Keyword: Corrugated surface

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A Study on the Possibility of Using of Spent RHDS Catalyst as a SCR Catalyst wash-coated on the metal corrugated substrate (폐 RHDS 촉매재생 후 메탈 코로게이트 지지체상에서 워시코팅에 의한 NOx 저감 SCR 촉매에 관한 연구)

  • Na, Woo-jin;Cha, Eunji;Kang, Dae-hwan;Go, Young-ju;Cho, Ye-ji;Choi, Eun-young;Park, Hea-Kyung
    • Journal of the Korean Applied Science and Technology
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    • v.37 no.4
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    • pp.723-732
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    • 2020
  • The spent RHDS (Residue HydroDeSulfurization) catalyst is deactivated mainly by deposition of various contaminants such as coke, sulfur and vanadium on the surface of catalyst. To eliminate those contaminants, the following remanufacturing process was conducted. The first, heavy oil on the surface of the spent RHDS catalyst was removed by kerosene and dehydrated. The second, the high temperature incineration was carried out to eliminate coke and sulfur components deposited on the surface of spent RHDS catalyst. The third, the excessive quantity of Vanadium deposited on the surface of catalyst was removed by leaching process as follows: ultrasonic agitation was carried out at 50℃, for 10 seconds with 0.5% and 1% oxalic acid solution. The purpose of this process is to find out regenerated RHDS catalyst can be used as SCR catalyst for NOx reduction by controlling the vanadium residual content of the regenerated RHDS catalyst through leaching process. The composition of regenerated RHDS catalyst was analyzed by XRF and the NOx reduction efficiency was also measured by continuous catalytic fixed bed reactor. As the result, regenerated catalyst, with 0.5% oxalic acid, ultrasonic agitation in 10 seconds, showed the most stable NOx reduction efficiency. Also, in comparison with commercial SCR catalyst, the NOx reduction performance of regenerated catalyst was similar to that of commercial SCR catalyst at the temperature 375℃ and higher whereas was lower than commercial SCR catalyst at the temperature range between 200~250℃. Therefore, it was confirmed that the regenerated catalyst as powder form wash coated on the surface of metal corrugated substrate can be used for commercial SCR catalyst.

Coupled Vibration of Moving Mass-Elastically Supported Beam Considering the Contact Stiffness (An Ananlytical Model of the Contact Force Fluctuation between Wheel and Rail) (이동질량-탄성지지무한보의 연성진동해석 (차륜.레일간의 접촉력 변동의 해석모델))

  • ;曄道 佳明;須田 義大;大野 進一
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1995.10a
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    • pp.197-200
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    • 1995
  • Corrugation of railway track can be caused by the various dynamic behavior of travelling wheels and track. In this paper, the coupled vibrations of travelling wheel and railway track are analyzed as the cause of corrugations. To analyze the coupled vibrations, the track supported by the sleepers and the traveling wheel are identified to the elastically supported infinite beam and the spring-mass system which runs at constant speed. The Hertzian contact spring is considered betwen the infinite beam and spring-mass system. The dynamic responses of elastically supported infinite beam and spring-mass system are calculated. The cause and development of rail corrugation are discussed in the view point of contact force fluctuation affected by the elastic supports and the corrugated surface profile of the track. By the obtained results, the possibilities of resonance are checked between the excitation by the corrugated surface profile and the natural frequency of contact spring-moving mass system. It may be thought to a development of railway corrugation.

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Effect of corrugation structure and shape on the mechanical stiffness of the diaphragm

  • Kim, Junsoo;Moon, Wonkyu
    • Journal of Sensor Science and Technology
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    • v.30 no.5
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    • pp.273-278
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    • 2021
  • Here, we studied the change in the mechanical stiffness of a diaphragm according to the corrugation pattern. The diaphragm consists of a silicon oxide and nitride double layer; a corrugation pattern was formed by dry etching, and the diaphragm was released by wet etching. The fabrication of the thin film was verified using focused ion beam and scanning electron microscopy images. The mechanical stiffness of the diaphragm was obtained by measuring the surface vibration using a laser Doppler vibrometer while applying external sound pressure. Flat squares, diaphragms with square corrugations, and circular corrugation patterns were measured and compared. The stiffness of the diaphragm with a corrugation structure was found to be smaller than that without a corrugation structure; in particular, circular corrugation showed a better effect because of the high symmetry. Furthermore, the effect of corrugation was theoretically predicted. The proposed corrugated diaphragm showed comparable flexibility with the state-of-the-art MEMS microphone diaphragm.

Investigation of Structural and Optical Properties of III-Nitride LED grown on Patterned Substrate by MOCVD (Patterned substrate을 이용하여 MOCVD법으로 성장된 고효율 질화물 반도체의 광특성 및 구조 분석)

  • Kim, Sun-Woon;Kim, Je-Won
    • Korean Journal of Materials Research
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    • v.15 no.10
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    • pp.626-631
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    • 2005
  • GaN-related compound semiconductors were grown on the corrugated interface substrate using a metalorganic chemical vapor deposition system to increase the optical power of white LEDs. The patterning of substrate for enhancing the extraction efficiency was processed using an inductively coupled plasma reactive ion etching system and the surface morphology of the etched sapphire wafer and that of the non-etched surface were investigated using an atomic force microscope. The structural and optical properties of GaN grown on the corrugated interface substrate were characterized by a high-resolution x-ray diffraction, transmission electron microscopy, atomic force microscope and photoluminescence. The roughness of the etched sapphire wafer was higher than that of the non-etched one. The surface of III-nitride films grown on the hemispherically patterned wafer showed the nano-sized pin-holes that were not grown partially. In this case, the leakage current of the LED chip at the reverse bias was abruptly increased. The reason is that the hemispherically patterned region doesn't have (0001) plane that is favor for GaN growth. The lateral growth of the GaN layer grown on (0001) plane located in between the patterns was enhanced by raising the growth temperature ana lowering the reactor pressure resulting in the smooth surface over the patterned region. The crystal quality of GaN on the patterned substrate was also similar with that of GaN on the conventional substrate and no defect was detected in the interface. The optical power of the LED on the patterned substrate was $14\%$ higher than that on the conventional substrate due to the increased extraction efficiency.

Influence of surfactant on heat transfer of air-cooled vertical absorber (공냉식 수직 흡수기의 열전달에 미치는 계면활성제의 영향)

  • 윤정인;권오경;문춘근
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.11 no.6
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    • pp.740-748
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    • 1999
  • This research was concerned with the enhancement of heat transfer by surfactant added to the aqueous solution of LiBr. Different vertical tubes were tested with and without an additive of normal octyl alcohol. The test tubes were a bare inner surface, groove inner surface, corrugated inner surface and spring inserted inner surface tubes. The additive concentration was about 0.08 mass%. The heat transfer coefficient was measured as a function of film Reynolds number in the range of 20~200. Experiments were tarried out at higher cooling water temperature of $35^{\circ}C$ to simulate an air cooling condition for several kinds of absorber testing tubes. The experimental results were compared with cases without surfactant. The enhancement of heat transfer by Marangoni convection effect which was generated by addition of the surfactant is observed in each test tube. Especially, it is clarified that the tube with an inserted spring has the highest enhancement effect.

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Improvement of Water Resistant Properties of a Linerboard for Corrugated Fiberboard Box by Coating with Na-alginate (알긴산 코팅에 의한 골판지 상자 제조용 라이너 원지의 수분저항성 증진)

  • Kim, Eun-Jung;Rhim, Jong-Whan;Kim, Byung-Yong
    • Korean Journal of Food Science and Technology
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    • v.38 no.6
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    • pp.762-766
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    • 2006
  • To improve water resistance of paperboard used to manufacture the corrugated boxes, effect of surface coating of the liner- board with Na-alginate was investigated by determining the optimum processing conditions such as a optimum alginate concentration for surface coating, plasticizer content, concentration of divalent cations their immersion times, For the surface coating of the liner-board, 2.5% Na-alginate solution was found to be the optimum concentration, and the concentration of glycerol used as plasticizer was effective when 35% alginate concentration was use was Used Immersion of the alginate coated paperboard for 3 min in a $CaCl_2$ solution improved the water resistance properties. As a divalent cation for the insolubilization of the alginate films, $Cu^{2+}$ was found to be as effective as $Ca^{2+}$. Among the platicizers tested, sorbitol was the most effective in reducing water vapor permeability and water solubility of alginate coated paperboard.

Joining Characteristics of Corrugated Polymer Surface by Laser (표면 요철 처리 된 광경화성수지의 레이저 접합 특성)

  • Yoon, Sung Chul;Choi, Hae-Woon
    • Laser Solutions
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    • v.18 no.4
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    • pp.6-11
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    • 2015
  • Specially designed and 3D printed samples were prepared and joined by a diode laser source. To increase the strength of joining and reliability of samples, the surface was patterned by using a 3D printer. The joining surface was prepared as hemispherical shape with no-patterns, 0.5mm pitch, 0.75mm pitch and 1mm pitch. The optical properties of samples were measured by using an integrated sphere where classical Kubelka-Munk theory and modified Richard-Mudgetts theory for the analysis applied. Scanning speed was set at 500mm/min and laser power was varied between 9 and 10watts for the preliminary joining characteristic analysis.

Atomic Force Microscopy Study of Conducting Layered Transition Metal Ditellurides

  • Kim Sung-Jin;Park So-Jung;Oh Hoon-Jung;Jeon, Il Cheol;Song Sunae
    • Bulletin of the Korean Chemical Society
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    • v.15 no.12
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    • pp.1098-1103
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    • 1994
  • Atomic force microscopy (AFM) images of two conducting layered transition-metal ditellurides, $TaTe_2$ and $Ta_{0.5}$$V_{0.5}$$Te_2$, were examined and their surface and bulk structural features were compared. All the measured unit cell parameters from AFM image were consistent and in complete agreement with the results of the X-ray diffraction. The microscopic structures of corrugated surface tellurium sheets were strongly affected by the modification of metal double zig-zag chains underneath Te surface. Large difference in the height amplitudes of AFM images in $TaTe_2$ and $Ta_{0.5}$$V_{0.5}$$Te_2$ phases was observed and this reflects large difference in the surface electron densities of two phases. On surface, the shorter intralayer Te…Te contacts in $TaTe_2$ induce more electron transfer from Te p-block bands to Ta d-block bands, thus electron density on surface observed in $TaTe_2$ is much lower than that of $Ta_{0.5}$$V_{0.5}$$Te_2$. However, in bulk, interlayer Te…Te contacts in V substituted phase are shorter than those in $TaTe_2$ phase, thus tellurium-to-metal electron transfer occurs more easily in $Ta_{0.5}$$V_{0.5}$$Te_2$ phase.

Development of a Computer Program for Bulk-type Container Design using Optimum Design Parameter Analysis (산물형 포장상자의 최적설계 요인분석에 의한 설계 프로그램 개발)

  • 박종민
    • Journal of Biosystems Engineering
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    • v.28 no.4
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    • pp.315-324
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    • 2003
  • If an optimum design technique is applied in the design of packaging container for bulk-type products, merits on the side of not only economic and compression performance but distribution efficiency are expected. Accordingly, minimum board area (mRBA), compression strength (CS) and compression strength per unit area (mCSPA) are important design parameters in optimum design of packaging container for bulk-type products. In this study, mathematical models for mRBA, CS and mCSPA of container as algorithm for optimum design program were developed. In order to develop these models, compression test by various dimensions of container and response surface analysis for mRBA, CS, and mCSPA of container were carried out. In the developed models, volume, W/L ratio and depth of container were principal independent variables. On the found of these models, optimum design program having faculties of outward and inward optimum design and information design was developed. Though the packaging specifications are same, required board area, board combination and cost of the corrugated board required container manufacture were greatly different by boundary conditions in outward design. Moreover, about 6.3∼10.1% in weight of container was lighter, and about 13.2∼25.6% in cost of container was reduced when the program was applied for 2 kinds of bulk-type products.