• Title/Summary/Keyword: w/c

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Statistical Life Prediction of Fatigue Crack Growth for SiC Whisker Reinforced Aluminium Composite (SiC 휘스커 보강 Al6061 복합재료의 통계학적 피로균열진전 수명예측)

  • 권재도;안정주;김상태
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.2
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    • pp.475-485
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    • 1995
  • In this study, statistical analysis of fatigue data which had obtained from respective 24 fatigue crack, was examined for SiC whisker reinforced aluminium 6061 composite alloy (SiC$_{w}$/A16061) and aluminium 6061 alloy. SiC volume fraction in composite alloy is 25%. The analysis results stress intensity factor range and 0.1 mm fatigue crack initiation life for SiC$_{w}$/A16061 composite & A16061 matrix are the log-normal distribution. And regression analysis by linear model, exponential model and multiplicative model were performed to find out the relationship between fatigue crack growth rate(da/dN) and stress intensity for find out the relationship between fatigue crack growth rate(da/dN) and stress intensity factor range(.DELTA.K) in the SiC$_{w}$/A16061 composite and examine the applicability of Paris' equation to SiC$_{w}$A16061 composite. Also computer simulation was performed for fatigue life prediction of SiC$_{w}$/A16061 composite using the statistical results of this study.udy.

Influences of Water to Cement Ratio and Chemical Admixtures on the Quality of Inter-Locking Block (인터로킹 블록의 품질에 미치는 물시멘트비와 화학혼화제의 영향)

  • 이상태;김기철;신병철;김진선;한천구
    • Proceedings of the Korea Concrete Institute Conference
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    • 1998.10c
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    • pp.157-160
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    • 1998
  • KS F 4419, which is dealt with the Inter-Locking block, states that water to cement ratio for manufacturing inter-locking block should be less than 25% and in KS F4419, the use of admixture is shown to be reluctant to recommend. In this paper, reinvestigation of some regulations in KS F 4419 are carried out. According to the experimental results, as W/C increases, flexural strength and compressive strength are tended to decrease, whereas they increases within certain range, Flexural strength and compressive strength have higher values in 1:2(W/C=35%), 1:4(W/C=45%) and 1:6(W/C=55%) of mix proportions. Moreover they have rather higher values with the containment of high range AE water-reducing agent. The absorption ratios decrease with the increase of W/C and the containment of high range AE water-reducing agent. Therefore, the regulations on the W/C and admixture in KS F 4419 reguire revision.

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WEYL SPECTRUM OF THE PRODUCTS OF OPERATORS

  • Cao, Xiaohong
    • Journal of the Korean Mathematical Society
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    • v.45 no.3
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    • pp.771-780
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    • 2008
  • Let $M_C=\(\array{A&C\\0&B}\)$ be a $2{\times}2$ upper triangular operator matrix acting on the Hilbert space $H{\bigoplus}K\;and\;let\;{\sigma}_w(\cdot)$ denote the Weyl spectrum. We give the necessary and sufficient conditions for operators A and B which ${\sigma}_w\(\array{A&C\\0&B}\)={\sigma}_w\(\array{A&C\\0&B}\)\;or\;{\sigma}_w\(\array{A&C\\0&B}\)={\sigma}_w(A){\cup}{\sigma}_w(B)$ holds for every $C{\in}B(K,\;H)$. We also study the Weyl's theorem for operator matrices.

W-B-C-N 확산방지막에서 질소농도에 따른 Stress 에 대한 연구

  • So, Ji-Seop;Lee, Channg-U
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2005.11a
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    • pp.72-73
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    • 2005
  • Stress behavior was studied to investigate the internal behaviors of boron, carbon, and nitrogen in the 1000${\AA}$-thick tungsten boron carbon nitride (W-B-C-N) thin films. The impurities in the W-B-C-N thin films provide stuffing effects that were very effective for preventing the interdiffusion between interconnection metal and silicon substrate during the subsequent high temperature annealing process. The resistivity of W-B-C-N thin film decreases as an annealing temperature increase. The W-B-C-N thin films have compressive stress, and the stress value decreased up to $4.11\times10^{10}dyne/cm^2$ as an $N_2$ flow rate increases up to 3 sccm.

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Thermophysical Properties of the Soybean Curd and Prediction of its Thermal Conductivity 1 Measurement of Thermophysical Properties of the Soybean Curd (두부의 전열물성 및 유효열전도도의 추정 1. 두부의 전열물성의 추정)

  • KONG Jai-Yul
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.15 no.3
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    • pp.211-218
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    • 1982
  • The specific heat capacity and density of soybean oil and soy protein composing of the soybean curd were measured between $30^{\circ}C\;and\;-40^{\circ}C$. The thermal conductivity of soybean oil was measured to be 0.160 and 0.140, $W/m{\cdot}K$ at unfrozen and frozen states, respectively. The effective thermal conductivity of the soybean curd depended not only on its water content but also on its fat and protein contents.

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A study on the effect of Ni-rich phase on the stress-rupture properties of Ni microalloyed W (W 활성소결체의 Ni-rich 상의 양이 응력 파단 성질에 미치는 영향에 관한 연구)

  • Park, Dae-Gyu;Kim, Su-Seong;Lee, Kyung-Sub
    • Korean Journal of Materials Research
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    • v.2 no.4
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    • pp.270-278
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    • 1992
  • The effect of Ni-rich phase on the stress-rupture properties of Ni mlcroalloyed W were studied using direct load creep tester at 100$0^{\circ}C$, 110$0^{\circ}C$, and 120$0^{\circ}C$ in $H_2.$ The stress rupture strength of 100hrs. of W-0.4wt% Ni was 43% higher at 100$0^{\circ}C$ and 35% higher at 110 $0^{\circ}C$than that of W-0.2wt% Ni due to the larger initial grain size, the higher relative density and the higher grain growth during test. That of W-0.8wt% Ni was 90% higher at 100$0^{\circ}C$ and 60% higher at 110$0^{\circ}C$ than that of W-0.2wt% Ni. The activation energy of W-0.4wt% Ni for creep was 81.3 Kcal/mole. It was considered that creep deformation was controlled by the diffusion of W in the Ni rich phase between the grains and the deformation of grains. All of the specimens showed intergranular fracture by grain boundary cavitation and growth of cavity throughout the entire spcimen cross-section.

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A SOC Design Methodology using SystemC (SystemC를 이용한 SOC 설계 방법)

  • 홍진석;김주선;배점한
    • Proceedings of the IEEK Conference
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    • 2000.06b
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    • pp.153-156
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    • 2000
  • This paper presents a SOC design methodology using the newly-emerging SystemC. The suggested methodology firstly uses SystemC to define blocks from the previously-developed system level algorithm with internal behavior and interface being separated and validate such a described blocks' functionality when integrated. Next, the partitioning between software and hardware is considered. With software, the interface to hardware is described cycle-accurate and the other internal behavior in conventional ways. With hardware, I/O transactions are refined gradually in several abstraction levels and internal behavior described on a function basis. Once hardware and software have been completed functionally, system performance analysis is performed on the built model with assumed performance factors and influences such decisions regressively as on optimum algorithm selection, partitioning and etc. The analysis then gives constraint information when hardware description undergoes scheduling and fixed-point trans- formation with the help of automatic translation tools or manually. The methodology enables C/C++ program developers and VHDL/Verilog users to migrate quickly to a co-design & co-verification environment and is suitable for SoC development at a low cost.

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Abstracts of Research Papers in Poultry Science (가금학 분야 연구 논문 초록)

  • 세계가금학회한국지부
    • Korean Journal of Poultry Science
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    • v.4 no.1
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    • pp.66-74
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    • 1977
  • 닭의 혈액상에 관한 발표는 많으나 아직 우리나라에서의 보고는 거의 없다. 이에 산난능력이 우수한 닭과 병계에 대한 앞으로의 혈액학적 연구를 위한 기초적자료를 얻고저 임상적으로 건강한 소위 한국 재내종(LCH)과 백색레그혼 (WLH)암탉의 정상 혈액학치 즉 적혈구, 백혈구, 혈색소, 헤마토크리프. 평균적혈구 용적, 평균 적혈구 혈색소량. 평균 적혈구 혈색소 농도 등을 조사하였다. 1 R.B.C.는 L.C.H.에서 3.18$\pm$0.10million per c$\mu$. mm였으며 W.L.H.는 3.23$\pm$0.05였다. 2. W.B.C.는 L.C.H에서 42.17$\pm$3.35, thousand per. c$\mu$mm였으며 W.L.H.는 35.64$\pm$2.89였다. 3. Hemoglobin치는 L.C.H.에서 11.24$\pm$0.30gm per 100$m\ell$였으며 WL.H.는 38.40$\pm$0.75였다. 4. Hematocrit치는 L.C.H.에서 34.00$\pm$0,98 percent였으며, W.L.H.는 33.40$\pm$0.75였다. 5. M.C.V.는 L.C.H에서 103.66$\pm$1.22 c$\mu$ 였으며, W.L.H.는 103.32$\pm$1.28이였다. 6. M.C.H,는 C.L.H.에서 34.19$\pm$0.41 $\mu$ $\mu\textrm{g}$9였으며. W.L.H,는 34.37$\pm$0.31이었다. 7. M.C.H.C는 L.C.H.에서 33.09$\pm$0.22 percent였으며, W.L.H.는 33.25$\pm$0.36 0.36이었다. (중략)

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