• 제목/요약/키워드: GRC

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Semi-analytical solutions of free and force vibration behaviors of GRC-FG cylindrical shells

  • Lei, Zuxiang;Tong, Lihong
    • Steel and Composite Structures
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    • 제32권5호
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    • pp.687-699
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    • 2019
  • In this paper, free and force vibration behaviors of graphene-reinforced composite functionally graded (GRC-FG) cylindrical shells in thermal environments are investigated based on Reddy's third-order shear deformation theory (HSDT). The GRC-FG cylindrical shells are composed of piece-wise pattern graphene-reinforced layers which have different volume fraction. Based on the extended Halpin-Tsai micromechanical model, the effective material properties of the resulting nanocomposites are evaluated. Using the Hamilton's principle and the assumed mode method, the motion equation of the GRC-FG cylindrical shells is formulated. Using the time- and frequency-domain methods, free and force vibration properties of the GRC-FG cylindrical shell are analyzed. Numerical cases are provided to study the effects of distribution of graphene, shell radius-to-thickness ratio and temperature changes on the free and force vibration responses of GRC-FG cylindrical shells.

길항미생물 Pseudomonas sp. GRC3의 식물병원균에 대한 항균력

  • 오지훈;박신;강선철
    • 한국생물공학회:학술대회논문집
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    • 한국생물공학회 2001년도 추계학술발표대회
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    • pp.660-661
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    • 2001
  • Pseudomonas sp. GRC3은 식물병원성 진균 P. capsici 에 대해 길항력을 가지며, 배양시 생성되는 가수분해 효소의 활성이 증가함에 따라 항진균력 또한 증가하여, 4일배양 시 균사 성장 저해율이 최대치를 기록하였다.

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IGCC 합성가스 냉각기 GRC의 열유동 및 입자거동 특성에 대한 전산해석 연구 (Numerical Simulations on the Thermal Flow and Particle Behaviors in the Gas Reversal Chamber of a Syngas Cooler for IGCC)

  • 박상빈;예인수;류창국;김봉근
    • 한국연소학회지
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    • 제18권1호
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    • pp.21-26
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    • 2013
  • In the Shell coal gasification process, the syngas produced in a gasifier passes through a syngas cooler for steam production and temperature control for gas cleaning. Fly slag present in the syngas may cause major operational problems such as erosion, slagging, and corrosion, especially in the upper part of the syngas cooler (gas reversal chamber, GRC). This study investigates the flow, heat transfer and particle behaviors in the GRC for a 300 MWe IGCC process using computational fluid dynamics. Three operational loads of 100%, 75% and 50% were considered. The gas and particle flows directly impinged on the wall opposite to the syngas inlet, which may lead to erosion of the membrane wall. The heat transfer to the wall was mainly by convection which was larger on the side wall at the inlet level due to the expansion of the cross-section. In the evaporator below the GRC, the particles were concentrated more on the outer channels, which needs to be considered for alleviation of fouling and blockage.

블록반응곡선을 이용한 불연속 암반내 공동에 대한 지보설계에 관한 연구

  • 이영주;이희근
    • 한국암반공학회:학술대회논문집
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    • 한국암반공학회 1995년도 정기총회 및 학술발표회
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    • pp.41-47
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    • 1995
  • NATM공법에서 지보는 주로 암반반응곡선(Ground Reaction Curve, GRC)상에서 설계된다. 그러나 GRC는 유도과정에서 많은 가정을 지니고 있어 시공에 직접 반영하기에는 많은 한계를 지닌다. 특히 과지압에 의한 소성거동의 문제가 심각하지 않고, 암반의 거동이 불연속면에 영향을 많이 받는 지역에서는 GRC의 가정 중에 하나인 등방 연속체라는 가정은 큰 결점 중의 하나이다. (중략)

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산화동물 모델 흰쥐 간세포에 대한 사삼(沙參), 양유근(羊乳根) 및 해방풍(海防風)의 항산화 효과 연구 (Study on the Anti-oxidative Effects of Adenophorae Radix, Codonopsis lanceolatae Radix and Glehniae Radix Cum Rhizoma on Liver Cells Isolated from Oxidatively Stressed Rat)

  • 민상홍;한효상;이영종
    • 대한본초학회지
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    • 제24권3호
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    • pp.109-119
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    • 2009
  • Objectives : The present study was purposed to compare Adenophorae Radix (henceforth AR), Codonopsis lanceolatae Radix (henceforth ClR) and Glehniae Radix cum Rhizoma (henceforth GRcR) concerning their anti-oxidant effect. Methods : We measured eythrocyte, leukocyte, thrombocyte, serum albumin, total bilirubin, LDL cholesterol, and glucose as well as SOD, GSH, catalase, NO, and MDA in the rat liver oxidatively stressed by AAPH. Results : 1. The oxidative stress-induced thrombocyte levels were significantly decreased in CIR-treated and GRcR-treated groups. 2. The oxidative stress-impaired SOD acitivities were significantly recovered in AR-treated and GRcR-treated groups. 3. The oxidative stress-reduced GSH contents were significantly increased in ClR-treated and GRcR-treated groups. 4. The oxidative stress-reduced catalase contents were significantly increased in all of the three groups. 5. The oxidative stress-induced NO productions were significantly decreased in all of the three groups. Conclusions : AR, ClR, and GRcR altogether showed the anti-oxidant effect in the rat liver oxidatively stressed by AAPH. The anti-oxidant properties of tAR, ClR, and GRcR seem to be similar even if those have different botanical properties and different medical efficacies in oriental medicine.

Genetic Distances in Two Gracilaria Species (Gracilariaceae, Rhodophyta) Identified by PCR Technique

  • Kim, Young Sik;Yoon, Jong-Man
    • 한국발생생물학회지:발생과생식
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    • 제22권4호
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    • pp.393-402
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    • 2018
  • Genomic DNA was isolated from the Gracilaria vermiculophylla (GRV) and G. chorda (GRC) from Jangheung located in the southern sea of the Korean Peninsula, respectively and we performed clustering analyses, DNA polymorphisms and the genetic differences. The seven selected primers OPC-01, OPA-04, OPA-05, OPD-07, OPD-08, OPB-10, and OPD-16 generated average bandsharing (BS) value, the genetic distance and dendrogram. The size of DNA bands varies from 90 bp to 2,400 bp. The average BS value was $0.859{\pm}0.004$ within GRV and $0.916{\pm}0.006$ within GRC. The average BS value between two Gracilaria species was $0.340{\pm}0.003$, ranged from 0.250 to 0.415. The dendrogram obtained by the seven primers, indicates two genetic clusters. The genetic distance between two Gracilaria species ranged from 0.059 to 0.513. The individual VERMICULOPHYLLA no. 07 of GRV was genetically closely related to VERMICULOPHYLLA no. 06 of GRV (genetic distance=0.059). Especially, two entities between the individual VERMICULOPHYLLA no. 10 of GRV and CHORDA no. 22 of GRC showed the longest genetic distance (0.513) in comparison with other individuals used. Accordingly, as mentioned above, PCR analysis showed that the GRV was a little more genetically diverse than the GRC species. We convinced that this DNA analysis revealed a significant genetic distance between two Gracilaria species pairs (p<0.01).

선배합방법에 의한 섬유보강 시멘트의 강도 특성에 관한 연구 (A Study on the Strength Properties of Glass Fiber Reinforced Cement made by Premixing Method)

  • 김용부;조정민
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 1990년도 봄 학술발표회 논문집
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    • pp.5-10
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    • 1990
  • There are two main methods in reinforcing cements with glass fibers : spray-suction and premixing method. But GRC have been mostly studied by spray technique. In order to develop GRC made by premixing method, in this paper, the influence of glass fiber length, volume content and curing conditions upon the compressive, direct tensile and bending strengths of composites fabricated by a premixing method, were investigated. According to the test results, although it was difficult to obtain perfectly uniform distribution of fibers in GRC Pannel, it was found that tensile strength of cements with glass fiber was improved 2~5 times and flexural strength 4 times compared to conventional cement mortar upto fiber length 35 mm, volume content 4%.

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A mathematical approach for the effect of the rotation on thermal stresses in the piezo-electric homogeneous material

  • Ramady, Ahmed;Dakhel, B.;Balubaid, Mohammed;Mahmoud, S.R.
    • Computers and Concrete
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    • 제25권5호
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    • pp.471-478
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    • 2020
  • In this work, the analytical solution for the stresses in piezo-thermo-elastic homogeneous, transversely isotropic material under the effect of the rotation has investigated. The thermoelasticity theory has used to study the problem. The material subjected to boundary conditions. Finally, the numerical solution has carried out piezo - thermo-elastic material under the effect of rotation, to illustrate the analytical development. The corresponding simulated results of various physical quantities such as the displacements and the stresses, the temperature and the electrical displacement have presented graphically.