• Title/Summary/Keyword: anchoring effect

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A study on development of methods to rehabilitate the damaged prestressed concrete beam using glass fiber (유리섬유를 이용한 손상된 프리스트레스트 콘크리트보의 보강공법 개발연구)

  • 한만엽;이택성;강원호
    • Proceedings of the Korea Concrete Institute Conference
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    • 1998.10b
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    • pp.815-820
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    • 1998
  • Many composite girder bridges have been constructed for about thirty five years. Nowadays they are aged or deteriorated because of th increase in traffic and vehicle loads. In this study, the effect of strengthening with glass fiber sheet is investigated to estimate the possibility for appling for damaged prestressed concrete bridges. One normal and eight cracked specimens which had been preloaded were tested. The cracked specimens were strengthened with either external prestressing or bonding glass fiber sheet, or using both methods. The results showed that the maximum loads are almost same for both methods. So it seems that the strengthening with glass fiber sheet can be used for strengthening damaged prestressed concrete girders. It is important that proper devices should be selected to prevent glass fiber sheet from premature bonding failure below its maximum load, which is similar to end anchorage problem in external prestressing method. It is proved that the devices proposed in this paper have sufficient anchoring capability to increase load carrying capacity.

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Switching characteristics of a pixel-isolated bistable twist-splay nematic liquid crystal cell

  • Song, Dong-Han;Lee, Seong-Ryong;Kim, Jae-Chang;Yoon, Tae-Hoon
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.502-504
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    • 2009
  • We demonstrate a pixel-isolated bistable twist-splay namatic (PI-BTSN) liquid crystal (LC) cell which has two stable states of splay and ${\pi}$-twist. Each state is stabilized by a multi-dimensional anchoring effect of pixel-isolating polymer walls without any chiral additives. Polymer walls are formed around the pixel region by anisotropic phase separation between LCs and reactive mesogens. Switching between the two states is archived by using vertical and horizontal electric fields. The memory mode of the fabricated LC cell has shown infinity memory time.

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Hysteretic Behavior of Wide Beam-Column joint (외부 넓은 보-기둥 접합부의 이력거동에 관한 연구)

  • Seo Soo-Yeon;Kim Jong-Sun;Yoon Yong-Dae;Lee Woo-Jin;Kim Sang-Sik;Yoon Seung-Joe
    • Proceedings of the Korea Concrete Institute Conference
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    • 2004.11a
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    • pp.623-626
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    • 2004
  • The purpose of this paper is to study the effect of longitudinal reinforcement for anchoring in the wide beam column joint as wall as the contribution of depth of spandrel beam to hysteretic behavior of the wide beam column joint. From the test it was shown that the specimen with anchorage in the joint had higher strength than the specimen with normal hook anchorage. Specimen with debonded reinforcement at out of Id from column face failed showing moved plastic hinge and less strength than normal specimen. However, the dissipated energy was increased $11\%$.

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Experimental Study on Wedge-type Anchorage System for CFRP Laminates (CFRP판용 쐐기형 정착장치에 대한 실험적 연구)

  • Park, Jong-Sup;Park, Young-Hwan;Jung, Woo-Tai
    • Proceedings of the Korea Concrete Institute Conference
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    • 2006.11a
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    • pp.157-160
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    • 2006
  • Carbon fiber reinforced polymer (CFRP) laminates can be used more efficiently in strengthening applications by applying prestress to the CFRP laminates. A key problem for prestressing with CFRP laminates is anchoring the laminates. These may include fracture to the CFRP laminates due to excessive gripping force or slippage of the CFRP laminates out of the anchorage zone caused by low friction between the anchor device and the lamiantes. The main objective of this study is the development of an applicative wedge-type anchorage system for prestressed CFRP laminates through experimental study. The experimental parameters were the type of anchorage and the effect of elastic modulus of tab. The test results showed that the developed anchor assures 100% CFRP laminate strength.

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Effects of Liquid Crystal Alignment on the Electro-Optical Characteristics of a-TN-LCD (a-TN-LCD의 전기광학특성에 미치는 액정배향의 효과)

  • 서대식;이창훈;황율연;이보호;이승희;김향율
    • Electrical & Electronic Materials
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    • v.10 no.1
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    • pp.15-19
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    • 1997
  • The characteristics of the response time and the viewing angle on twisted nematic (TN) liquid crystal display (LCD) and amorphous (a)-TN-LCD without rubbing were investigated. To measure the tansmission-voltage, response time, and viewing angle characteristics, we prepared three kinds of LC cells and then studied the surface liquid crystal alignment effect. It was found that the response time on A-TN-LCD was fast compared to the TN-I-CD, and the weak anchoring strength was attributed to the fast response time on a-TN-LCD. Also, we obtained the wide viewing angle characteristics on a-TN-LCD. The liquid crystal alignment of LCD device for electro-optical characteristics is discussed in the present paper.

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The Effects of Surface Pretreatments on Adhesion Strength of TiN Films by DC Magnetron Sputtering (표면전처리가 반응성 스퍼터링법으로 제조한 TiN 코팅층의 밀착력에 미치는 영향)

  • 김흥윤;백운승;권식철;김규호
    • Journal of Surface Science and Engineering
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    • v.26 no.5
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    • pp.225-234
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    • 1993
  • Titanium nitride coatings were deposited onto SUS304 stainless steel substrates pretreated by mechanical scrubbing, chemical etching at 50% HCl solution and Ar ion etching. Adhesion strength were measured by scratch tester and confirmed by SEM with EDS. Adhesion strength of Ar ion etched substrate was 10 to 15 times higher than that of mechanical scrubbed or chemical etched substrate. Ar ion etching brought about an uniform and fine spherical shaped surface, while chemical etching gave rise to a rough and irregular surface on SEM micrograph. It was suggested that higher adhesion strength might be caused by anchoring effect of Ar ion etched surface prior to TiN deposition.

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Asperities on the Surface of Plate-like Alumina and their Effect on Nacre-inspired Alumina-PMMA Composites

  • Kim, Bo-Yeon;Lee, Yoonjoo;Kim, Soo-Ryong;Shin, Dong-Geun;Kwon, Woo-Teck;Choi, Duck-Kyun;Kim, Younghee
    • Journal of the Korean Ceramic Society
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    • v.52 no.4
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    • pp.248-252
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    • 2015
  • Natural materials often have unique mechanical properties, such as the hierarchical structure of nacre formed through mineral bridges or asperities created between an inorganic particle and a natural-layer surface. As these asperities produce an exceptional shear resistance, in this study, we aimed to emulate the natural structure of nacre by synthesizing inorganic asperities and mineral bridges with different temperatures in the range of $1100-1300^{\circ}C$ and clay contents from 10 - 50 wt%. Following the infiltration of methyl methacrylate, we measured the mechanical properties to assess whether they were improved by the asperities. It was confirmed that the asperities improved the bending strength by 10%, and the anchoring effect was observed on the fracture surface.

Pullout Test of Reinforcement with End Mechanical Anchoring Device (단부 기계적 정착장치를 갖는 철근의 뽑힘강도)

  • 김용곤;임원석;최동욱
    • Journal of the Korea Concrete Institute
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    • v.14 no.3
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    • pp.430-439
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    • 2002
  • The development of reinforcing steel is required in reinforced concrete structures. The standard hooks that have been widely used for the tensile development in the beam-column joints tend to create difficulties of construction such as steel congestion as the member cross sections are becoming smaller due to the use of higher strength concrete and higher grade steel. Using the reinforcing bars with end mechanical anchoring device (headed reinforcement) provides potential economies in construction such as reduction in development lengths, simplified details, and improved responses to cyclic loadings. In this paper, the pullout strengths and behaviors of the headed reinforcement were experimentally studied. In 33 pullout tests performed using D25 deformed reinforcing bars, the test parameters were embedment depth, edge distance, head size, and the use of transverse reinforcement. The pullout strengths determined from tests closely agreed with the pullout strengths predicted using the CCD method. The pullout strengths increased with increasing embedment depths nd edge distances. The strengths tend to increase with the use of larger heads. From the experimental program where the effect of the transverse reinforcement was examined, a modification factor to the CCD was suggested to represent the effect of such reinforcement that is installed across the concrete failure plane on the pullout strengths.

Application effect and limitation of AHP as a research methodology -A comparison of 3 statistical technique for evaluating MIS success factor- (AHP 기법의 적용효과및 한계점에 관한 연구 -MIS 성공요인평가를 위한 3가지 통계기법 비교중심-)

  • 윤재곤
    • Journal of the Korean Operations Research and Management Science Society
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    • v.21 no.3
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    • pp.109-125
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    • 1996
  • Biases and errors in the human being's reasoning process have been studied continuously by the researchers, especially psychlogists and social scientists. These bias phenomenon is classified on the basis of the origin, i. e. motivation and cognition. Furthermore the necessity of research on the bias in the management and management information system areas in increased more and more recently, which have their academic backgrounds in the psychology and social science. The biased information stream is transformed into the systematic error due to the motivation and cognitive bias of human-being, then its resulting phenomena are as follows; 1. the availability of salient information 2. preconceived ideas or theories about peoples and event 3. anchoring and perseverence phenomena. In order to reduce the information errors, Satty suggested the Analytic Hierarchy Process (AHP) that is the subject of this paper and that is widely used for evaluation of complex decision making alternatives. THerefore this paper studies AHP's effects and its limitations in applying to the management area. Thus this paper compared the performances of the 3 models : 1 the traditional additive regression model. 2 regression model using the factor score, and 3 the regression model with AHP. As a result, 3 models produce the different outcomes.

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Ginseng total saponin modulates podocyte p130Cas in diabetic condition

  • Ha, Tae-Sun;Lee, Jin-Seok;Choi, Ji-Young;Park, Hye-Young
    • Journal of Ginseng Research
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    • v.37 no.1
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    • pp.94-99
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    • 2013
  • Proteinuric conditions demonstrate structural and compositional changes of the foot processes and slit diaphragms between podocytes. p130Cas in podocytes serves as an adapter protein anchoring glomerular basement membrane to actin filaments of podocyte cytoskeleton. To investigate the effect of ginseng total saponin (GTS) on the pathologic changes of podocyte p130Cas induced by diabetic conditions, we cultured mouse podocytes under: 1) normal glucose (5 mM, control); 2) high glucose (HG, 30 mM); 3) advanced glycosylation endproducts (AGE)-added; or 4) HG plus AGE-added conditions and treated with GTS. In confocal imaging, p130Cas colocalized with zonula occludens-1 and synaptopodin connecting to F-actin. However, diabetic conditions relocalized p130Cas molecules at perinuclear cytoplasmic area and reduced the intensity of p130Cas. In Western blotting, diabetic conditions, especially HG plus AGE-added condition, decreased cellular p130Cas protein levels at 24 and 48 h. GTS improved such quantitative and qualitative changes. These findings imply that HG and AGE have an influence on the redistribution and amount of p130Cas of podocytes, which can be reversed by GTS.