• Title/Summary/Keyword: the base

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Study on the Effective Stiffness of Base Isolation System for Reducing Acceleration and Displacement Responses

  • Kim, Young-Sang
    • Nuclear Engineering and Technology
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    • v.31 no.6
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    • pp.586-594
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    • 1999
  • To limit both the large displacement and acceleration response of the structure efficiently, the relationships between acceleration and displacement responses of the structure under several earthquakes are investigated for various horizontal stiffness of the base isolation system to determine the effective stiffness of the base isolation system in this paper. An example structure is a five-storey steel frame building as the primary structure and the secondary structures are assumed to be located on the fifth floor of the primary structure. Input motions used in the structural analysis are El Centre 1940, Taft 1952, Mexico 1985, San Fernando 1971 Pacoima Dam, and artificially generated earthquakes. The relationships of the absolute peak acceleration and the displacement at the top of the structure are calculated for various natural periods of base isolators under various earthquakes. The peak acceleration response of the fifth floor in the base isolated structure is significantly reduced by a factor of 2.1 through 6.25. Also, the relative displacement response of the floor to the base of the superstructure is very small. The results of this study can be utilized to determine the effective stiffness of the base isolation system.

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Comparison of shear, tensile and shear/tensile combined bonding strengths in bracket base configurations (브라켓 기저부 형태에 따른 전단, 인장, 전단/인장복합결합강도의 비교)

  • Lee, Choon-Bong;Lee, Seong-Ho;Kim, Jong-Ghee
    • The korean journal of orthodontics
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    • v.29 no.5 s.76
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    • pp.599-611
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    • 1999
  • The purpose of this study was to evaluate shear, tensile and shear/tensile combined bond strengths(SBS, TBS, S/TBS) in various orthodontic brackets bonded to human teeth with chemically cured adhesive (Ortho-one, Bisco, USA). Five types of metal brackets with various bracket base configurations (Micro-Loc base(Tomy, Japan), Chessboard base(Daesung, Korea), Non-Etched Foil Mesh base(Dentarum, Germany), Micro-Etched Foil Mesh base(Ortho Organiners, USA), Integral base(Unitek, USA)) were used in this study. Shear, tensile and shear/tensile combined bond strengths according to the direction of force were measured by universal testing machine. The bracket base surface after bond strength test were examined by stereoscope and scanning electron microscope. The assessment of resin remnant on bracket base surface was carried out by ARI(adhesive remnant index). The results obtained were summarized as follows, 1. In all brackets, SBS was in the greatest value(p<0.05), TBS was in 50% level and S/TBS was in 30% level of SBS. 2. In bond strength, Micro-Loc base bracket showed the maximum bond strength($SBS:22.86{\pm}1.37kgf,\;TBS:11.37{\pm}0.42kgf,\;S/TBS:6.69{\pm}0.34kgf$) and Integral base bracket showed the minimum bond strength($SBS:10.52{\pm}1.27kgf,\;TBS:4.27{\pm}1.08kgf,\;S/TBS:2.94{\pm}0.58kgf) (p<0.05). 3. In bond strength per unit area, Integral base bracket showed the minimum value, Micro-Loc base and Chessboard base brackets were in similar value(p>0.05). Non-Etched Foil Mesh base and Micro-Etched Foil Mesh base bracket were similar in SBS and TBS(p>0.05), but Micro-Etched Foil Mesh base bracket was greater than Non-Etched Foil Mesh base bracket in S/TBS(p<0.05). 4. Bond failure sites were mainly between bracket base and adhesive, therefore ARI scores were low.

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Literature Review on the Korean Traditional Soft Drinks Base on the Omija Broth (五味子汁를 기본으로 한 飮淸類의 고찰)

  • 이정숙
    • Journal of the East Asian Society of Dietary Life
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    • v.3 no.1
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    • pp.19-25
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    • 1993
  • The types and processing characteristics of traditional soft drinks base in omija broth and their historical back grounds were surveyed trough the old literatures published. Three group classification of Korean traditional soft drinks base in omija broth. 1. Honeyed juice mixed fruits base in omija broth 2. Honeyed juice mixed cereal cooking and noodles base on omija borth 3. A water shortage and tea base in omija broth

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Analysis and Optimization based on the Fixed Fin Base Height for a Triangular Fin (삼각 핀의 해석과 고정된 핀 바닥 높이에 기준한 최적화)

  • Kang, Hyung-Suk
    • New & Renewable Energy
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    • v.3 no.1 s.9
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    • pp.13-19
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    • 2007
  • A triangular fin with variable fin base thickness and base height is analyzed and optimized for the fixed fin base height using a two-dimensional analytical method. At the middle of the fin length, the variation of the temperature along the fin height is listed. The influences of the fin length, base thickness and base height on the heat loss and fin efficiency are analyzed, The optimum heat loss, corresponding optimum efficiency and optimum fin length as a function of the fin base thickness are presented. The optimum heat loss and optimum fin tip length as a function of the convection characteristic number are represented.

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Echelon Base Stock Policy with Outside Competition in a Two-Stage Supply Chain (외부 경쟁을 고려한 두 단계 공급체인에서의 단계기본재고수준의 결정)

  • Kim, Nam-Young
    • Journal of the Korean Operations Research and Management Science Society
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    • v.30 no.4
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    • pp.71-81
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    • 2005
  • This Paper focuses on the effects of outside competition on an optimal echelon base stock level in a two stage supply chain. This is new in that we have been studying the effects of inside competition within a supply chain up to now. It is known that the optimal echelon base stock level with inside competition within a supply chain is less than the global optimal echelon base stock level without inside competition. This is due to the ' public goods ' nature of inventory. That is, more inventory is better, but one wants the other to invest more, thus resulting in under-investment. However, this phenomenon becomes weaker as outside competition increases. We show that as outside competition becomes stronger, the ' public goods ' effects decrease and the optimal echelon base stock level increases. If the level of competition is sufficiently high, the optimal echelon base stock level goes even higher than the global optimal echelon base stock level. We develop a theoretical model for the analysis and conduct a numerical analysis.

Seismic Response of Base-Isolated Liquid Storage Tanks Considering Liquid-Structure-Soil Interaction (유체-구조물-지반 상호작용을 고려한 면진된 유체저장탱크의 3차원 지진응답)

  • 조성용;김문겸;임윤묵
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2002.09a
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    • pp.98-105
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    • 2002
  • The effects of the base-isolation system and elastic soil foundation on the behavior of a liquid storage tank are studied. To evaluate the seismic response of liquid storage tank accurately, the coupled dynamic system considering base isolation and soil interaction problem is formulated in time domain. Results show that the base isolation system reduces effectively the radial displacements, base shears, overturning moments, axial resultant stresses and the hydrodynamic pressure by providing flexibility and energy dissipation capability. Base Isolation may, however, increase the relative liquid sloshing amplitude due to the effect of liquid-structure interaction and cause excessive large relative displacements between structure and foundation. In addition to base-isolator, the dynamic behavior of liquid storage tank is related to the flexibility of base foundation, so the analysis of soil-structure interaction s achieved.

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A Computational Study of a Supersonic Flow with Base Bleed (Base Bleed 를 가지는 초음속 유동에 대한 수치해석적 연구)

  • Lee, Young-Ki;Kim, Heuy-Dong;Raghunathan, Srinivasan
    • Proceedings of the KSME Conference
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    • 2004.04a
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    • pp.1589-1594
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    • 2004
  • A numerical analysis has been performed to give an understanding of the physics of a compressible base flow with mass bleed in a Mach 2.47 freestream. Axisymmetric, compressible mass-averaged Navier-Stokes equations are computed using a two-equation turbulence model, standard ${\kappa}-{\omega}$, and a fully implicit finite volume scheme. The mass bleed is characterized by the change in the mass flow rate of the bleed jet non-dimensionalized by the product of the base area and freestream mass flux. The result showing that there is an optimum bleed condition with maximum base pressure, leading to a minimum base drag, is clearly predicted and the validation with experimental data shows reasonable agreement.

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The Effect of Base Metal Grain Boundary on Isothermal Solidification Phenomena during TLP Bonding of Ni Base Superalloys (액상확산접합한 Ni기 초내열합금의 등온응고거동에 미치는 모재결정입계의 영향)

  • 김대업
    • Journal of Welding and Joining
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    • v.19 no.3
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    • pp.325-333
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    • 2001
  • The effect of base metal grain size on isothermal solidification behavior of Ni-base superalloy, CMSX-2 during transient liquid phase (TLP) bonding was investigated employing MBF-80 insert metal. TLP-bonding of single crystal. coarse-grained and fine-grained CMSX-2 was carried out at 1373∼1548k for various holding time in vacuum. The eutectic width diminished linearly with the square root of holding time during isothermal solidification process for single crystal, coarse-grained and fine-grained base metals. The completion time for isothermal solidification decreased in the order ; single crystal, coarse-grained and fine-grained base metals. The difference of isothermal solidification rates produced when bonding the different base metals could be explained quantitatively by the effect of base metal grain boundaries on the apparent average diffusion coefficient of boron in CMSX-2.

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Single-Fiber Bidirectional Transmission System Using Base Station Without Light Sources (광원이 없는 Base Station을 이용한 단일 광섬유 양방향 전송 시스템)

  • 전금수;정용채;임명섭;반재경
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.28 no.5A
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    • pp.323-332
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    • 2003
  • We have proposed and implemented a novel cost-effective optical subcarrier mutiplexing transceiver for base station without light sources in which optical signal can be transmitted bidirectionally over a single optical fiber. Modulated optical signal is retransmitted from the base station to the central office using a ring-type base station which consists of a circulator and an Mach-Zehnder modulator, where the optical source is supplied from the central office. In order to investigate the feasibility of the proposed base station without light sources, we have measured adjacent channel power ratio and carrier to noise ratio by transmitting the IS-95 CDMA signal and 14 tones carrier signal bidirectionally through the system.

Utilization of Pine Bark(II) -Characterization of Mg- and Na-base Acid Sulfite Cooking- (소나무 수피(樹皮)의 총합적(總合的) 이용(利用)(II) -Mg- 및 Na-base 산성(酸性) 아황산염(亞黃酸鹽) 증해(蒸解) 특성(特性)-)

  • Mun, Sung-Phil;Kim, Jae-Phil
    • Journal of the Korean Wood Science and Technology
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    • v.22 no.1
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    • pp.34-39
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    • 1994
  • Effects of Mg-base acid sulfite and Mg- or Na-base bisulfite on pine bark cooking were examined. In the presence of 75 % free acid at 145 $^{\circ}C$, the rate of cooking and delignification was improved with the increase of total acid. However, the delignification could not be achieved by 50 % or more under these cooking conditions. When cooked with 50~65 % free acid and at 155~165 $^{\circ}C$, the rate of cooking and delignification was remarkably improved. Thus, the bark was delignified up to 73 % when cooked for 2 hours in the presence of 50 % free acid and 24 % total acid. Na-base bisulfite was slightly more effective than Mg-base bisulfite for cooking, giving 76 % delignification of pine bark. However, there was no significant difference in selectivity of delignification between Na- and Mg-base bisulfite cooking.

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