• Title/Summary/Keyword: w/c

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An Engineering Properties of Concrete Containing Waste Glass (폐유리를 혼입한 콘크리트의 공학적 특성)

  • 라재웅;신재인;오성진;구봉근
    • Proceedings of the Korea Concrete Institute Conference
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    • 2000.10a
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    • pp.138-143
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    • 2000
  • In this paper, we carried out experiment to use crushed waste glass as a fine aggregate. This study delt with the comparative analysis on the construction works and engineering properties of concrete containing crushed waste glass through physical experiment. The experimental variables are crushed waste glass substitution ratio and W/C(38, 53%). When the W/C was 38%, we could know that concrete containing crushed waste glass was good as general concrete on the construction works and engineering properties but the concrete containing crushed waste glass applied W/C 53% was not good as general concrete on those. Therefore, concrete containing crushed waste glass applied W/C 53% should use admixture on the site.

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An Experimental Study on the Optimum water-cement ratio of Antiwashout underwater concrete (수중불분리콘크리트의 최적 W/C에 관한 연구)

  • 윤재범;어영선;김종수;김명식;백동일
    • Proceedings of the Korea Concrete Institute Conference
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    • 1998.04a
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    • pp.277-283
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    • 1998
  • In this study we changed W/C into 45, 50, 55, 60%, mixed sea sand which is often used as a replacing aggregate according to the lack of recourse with river sand in the ratio of 5:5 and producted antiwashout underwater concrete. We measured slump flow, air value, pH and suspension in the fresh concrete. After testing each W/C through unit weight and compressive strength of specimen which is produced and cured in the air and salt water it was founded that if sea sand was properly used after salt manufacturing, there will be no bad influence to antiwashout underwater concrete. The characteristic of them showed excellent, when W/C was 50%.

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Design a XML DBMS using RDBMS Based on XML Schema (관계형 DBMS를 이용한 XML 스키마 기반에 XML DBMS 설계)

  • Lee Sang-Tae;Lim Jong-Seon;Joo Kyung-Soo
    • Journal of the Korea Society of Computer and Information
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    • v.9 no.4 s.32
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    • pp.19-26
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    • 2004
  • XML DTD is defining expression of simple form for XML document, there is much difficulties to define structure of XML document. Solving XML DTD's problem, W3C was select XML schema by standard in 2001. This paper proposes a design to XML DBMS using Relational Database based on XML schema to be selected by standard from W3C to overcome XML DBMS's shortcoming using XML DTD.

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Riccati Equation and Positivity of Operator Matrices

  • Fujii, Jun Ichi;Fujii, Masatoshi;Nakamoto, Ritsuo
    • Kyungpook Mathematical Journal
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    • v.49 no.4
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    • pp.595-603
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    • 2009
  • We show that for an algebraic Riccati equation $X^*B^{-1}X-T^*X-X^*T=C$, its solutions are given by X = W + BT for some solution W of $X^*B^{-1}X$ = $C+T^*BT$. To generalize this, we give an equivalent condition for $\(\array{B&W\\W*&A}\)\;{\geq}\;0$ for given positive operators B and A, by which it can be regarded as Riccati inequality $X^*B^{-1}X{\leq}A$. As an application, the harmonic mean B ! C is explicitly written even if B and C are noninvertible.

콘크리트에서의 방사성핵종 확산계수

  • 금동권;조원진;한필수
    • Proceedings of the Korean Nuclear Society Conference
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    • 1995.05b
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    • pp.839-844
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    • 1995
  • 처분장 구조물의 주요방벽 재료중의 하나인 콘크리트에서의 핵종확산계수를 측정하기 위하여 내부확산법을 적용하였다. 핵종은 양이온과 음이온을 대표하는 Cs 과 I 이었으며, 고체 시료는 양생된 순수시멘트 또는 시멘트와 모레를 섞은 몰타르로 물과 시멘트의 비 (W/C) 를 변화시켰다. 용액은 표준 제조방법에 따라 제조된 합성지하수이었다. Curve fitting 법을 이용한 모델과 실험의 비교로부터 핵종의 확산계수를 계산하였다. 순수시멘트의 경우 Cs 의 겉보기 확산계수는 1.7 $\times$ $10^{-12}$~1.4 $\times$ $10^{-11}$ m$^2$/sec 의 범위로 W/C 가 증가할수록 컸으며 I 는 2.9 $\times$ $10^{-14}$ ~ 1.0 $\times$ $10^{-l3}$ $m^2$/sec의 범위로 또한 W/C 에 따라 증가하였다. 몰타르의 경우 W/C 가 클수록 Cs 의 확산계수는 증가하였으나 I 에 대해서는 큰 변화를 보여주지 않았다 본 실험에서 얻어진 핵종의 유효확산계수값이 $10^{-13}$ ~ $10^{-10}$ m$^2$/sec의 범위를 갖는 것으로 보아 공극확산이 핵종확산의 지배 메커니즘임이 예상되었다.

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An Effects of Horizontal Continuous Vibration on the Strength of Concrete as to W/C Variation (W/C를 변화시킨 콘크리트의 강도에 수평연속진동이 미치는 영향)

  • 정병훈;손영근;이환우;김명식
    • Proceedings of the Korea Concrete Institute Conference
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    • 2000.10b
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    • pp.1189-1194
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    • 2000
  • The purpose of this investigation is to establish which consequence is happen about initial curing concrete's compressive strength of 7days, 28days which changes W/C ratio by the change of vibrating speed and vibrated time. An experimental parameter is fixed 4 degrees of W/C ratio(45%, 50%, 55%, 60%), 3 degrees of vibrated time(3hr, 6hr, 12hr) and different vibrating speed(0.25kine, 0.5kine, 1kine). As the result, compressive strength of 7days was increased when vibrating speed and vibrated time is 1kine, 12h and also compressive strength of 28days was increased when vibrating speed and vibrated time is 0.25kine and 3hr.

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A Study on the Dielectric Properties of PZT Ceramics with 2 and 6 Valent Additives (2가 및 6가의 첨가제에 따른 PZT 자기의 유전적 성질에 관한 연구)

  • 안영필;이기옥
    • Journal of the Korean Ceramic Society
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    • v.20 no.1
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    • pp.19-24
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    • 1983
  • Dielectrics used as capacitor was studied in the system of $Pb(MgW)_{0.5} O_3-PbTiO_3-PbZrO_3$ Curie tempera-tures of $PbTiO_3 PbZrO_3$ and $Pb[MgW]_{0.5} O_3$ were 49$0^{\circ}C$ 23$0^{\circ}C$ and 39$0^{\circ}C$ respectively. When these materials formed solid solution the more amount of $Pb(MgW)_{0.5}O_3$ was increased the more Curie temperature lowered and dielectric constant increased. Higher dielectric constants were measured in the solid solution of which X-Ray diffraction patterns were changed. Especially Curie temperature and dielectric constant were 85$^{\circ}C$ and 4159 respectively in the composition of 60 $Pb(MgW)_{0.5}O_3-30 PbTiO_3-10PbZrO_3$. Also in this composition ferroeletric material with thermal stability was obtained.

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Object Detection Using Deep Learning Algorithm CNN

  • S. Sumahasan;Udaya Kumar Addanki;Navya Irlapati;Amulya Jonnala
    • International Journal of Computer Science & Network Security
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    • v.24 no.5
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    • pp.129-134
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    • 2024
  • Object Detection is an emerging technology in the field of Computer Vision and Image Processing that deals with detecting objects of a particular class in digital images. It has considered being one of the complicated and challenging tasks in computer vision. Earlier several machine learning-based approaches like SIFT (Scale-invariant feature transform) and HOG (Histogram of oriented gradients) are widely used to classify objects in an image. These approaches use the Support vector machine for classification. The biggest challenges with these approaches are that they are computationally intensive for use in real-time applications, and these methods do not work well with massive datasets. To overcome these challenges, we implemented a Deep Learning based approach Convolutional Neural Network (CNN) in this paper. The Proposed approach provides accurate results in detecting objects in an image by the area of object highlighted in a Bounding Box along with its accuracy.

Effect of Grain Size on Corrosion Resistance and High Temperature Oxidation Behavior of 22Cr-15Ni-5W Super Austenitic Stainless Steels (22Cr-15Ni-5W 슈퍼 오스테나이트계(系) 스테인리스강(鋼)의 고온산화(高溫酸化) 및 내식성(耐蝕性)에 미치는 결정립(結晶粒) 크기의 영향(影響))

  • Kim, H.J.;Lee, H.W.;Lee, J.M.;Kang, C.Y.
    • Journal of Power System Engineering
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    • v.10 no.3
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    • pp.51-57
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    • 2006
  • The effect of grain size on corrosion resistance and high temperature oxidation behavior was studied in 22Cr-15Ni-5W super austenitic stainless steels for desulfurization equipment as a heat power station. In the high temperature oxidation test, oxidation rate was increased as the temperature increased from $600^{\circ}C\;to\;800^{\circ}C$. In vapor, oxidation rate was faster than that in air. Because the vapor was inhibited nucleation of $Cr_2O_3$ film. And the high temperature oxidation resistance at $600^{\circ}C{\sim}800^{\circ}C$ was excellent from all specimens and specimen of the smallest grain size was the most excellent. Because increasing of diffusion course through the grain-boundary was promoted nucleation and growth of $Cr_2O_3$ film. In the test temperature at $600^{\circ}C{\sim}800^{\circ}C$, Cr rich round particle oxide was formed in air, whereas Fe rich needle type oxide was developed in vapor.

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The Structures and Dielectric Properties of Plasma Polymerized Polyethylene (플라즈마 중합 폴리에틸렌 구조와 유전특성)

  • 김두석
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.14 no.3
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    • pp.38-42
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    • 2000
  • Plasma polymerized thin films were manufactured inter-electrode coupled plasma polymerization apparatus. The deposition rate reached its maximum between 40[W] and 100[W]. In the ESCA analysis, peaks revealing -CH2, -CH, -C- were present at 285.4 and 285.5[eV] respectively. The C=O peak at 532.8[eV] and the C-O peak at 533.8[eV], which were grouped with an unignorable amount of oxygen were conformed. In ESR analysis, the curve revealing strong amplification was in saturation, which was affected by weak power. This is considered as a -CH-Ch=Ch- structure containing the Allyl group. The relative permittivity of the plasma polymerized thin films was about 3.5 at a frequency of 100[Hz]∼200[kHz]. The dissipation factor showed allow value of 0.008.

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