• 제목/요약/키워드: P-space

검색결과 2,781건 처리시간 0.03초

내연기관용 슬라이드 베어링재의 케비테이션 침식거동과 부식영향 및 윤할유의 거동에 관한 연구 (A Study on the behaviour of Cavitation erosion and lubricating Oils and the influence of Corrosion on Slide Bearing Metals for Internal combustion Engine)

  • 이진열;임우조
    • 수산해양기술연구
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    • 제28권2호
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    • pp.171-183
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    • 1992

  • In this paper, the behaviour of cavitation erosion, influence of corrosion and corrosion control on slide bearing metals for internal combustion engine were investigated, and this experiment was done by the vibratory cavitation erosion tester. The main results obtained are as follows: 1. With decreasing the space between horn and specimen, the weight loss and its rate increased step by step. But the weight loss and its rate of 0.2mm space decreased conversely more than that of 0.4mm space at early stage. 2. The weight loss and its rate with change of pH were appeared to the order of pH2>pH12>pH7>pH4. And the weight loss and its rate at pH 4 decreased at best. 3. The weight loss and its rate by cavitation erosion for bearing metals were shown to the order of W.M7>W.M1>K.M4. 4. There appeared mainly small pit hole at pH2, and appeared the pit of netting thread type at pH12 by the results of the damaged surfaces at pH2 and pH12 environments that were sensitive to cavitation erosion. 5. With increasing the viscosity of lubricating oil, the weight loss rate by cavitation erosion became dull at the space below 0.5mm. 6. The protective efficiency of cavitation erosion-corrosion is superior inhibitor of chormate(25 ppm) to cathodic protection.

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Effect of Vitamin E Supplementation on Intestinal Barrier Function in Rats Exposed to High Altitude Hypoxia Environment

  • Xu, Chunlan;Sun, Rui;Qiao, Xiangjin;Xu, Cuicui;Shang, Xiaoya;Niu, Weining;Chao, Yu
    • The Korean Journal of Physiology and Pharmacology
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    • 제18권4호
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    • pp.313-320
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    • 2014

  • The study was conducted to investigate the role of vitamin E in the high altitude hypoxia-induced damage to the intestinal barrier in rats. Sprague-Dawley rats were divided into control (Control), high altitude hypoxia (HH), and high altitude hypoxia + vitamin E (250 mg/kg $BW^*d$) (HV) groups. After the third day, the HH and HV groups were placed in a hypobaric chamber at a stimulated elevation of 7000 m for 5 days. The rats in the HV group were given vitamin E by gavage daily for 8 days. The other rats were given equal volume saline. The results showed that high altitude hypoxia caused the enlargement of heart, liver, lung and kidney, and intestinal villi damage. Supplementation with vitamin E significantly alleviated hypoxia-caused damage to the main organs including intestine, increased the serum superoxide dismutase (SOD) (p< 0.05), diamino oxidase (DAO) (p< 0.01) levels, and decreased the serum levels of interleukin-2 (IL-2) (p< 0.01), interleukin-4 (IL-4) (p<0.001), interferon-gamma ($IFN-{\gamma}$) (p<0.01) and malondialdehyde (MDA) (p<0.001), and decreased the serum erythropoietin (EPO) activity (p<0.05). Administration of vitamin E significantly increased the S-IgA (p<0.001) in ileum and significantly improved the expression levels of occludin and $I{\kappa}B{\alpha}$, and decreased the expression levels of hypoxia-inducible factor 1 alpha and 2 alpha ($HIF-1{\alpha}$ and $HIF-2{\alpha}$), Toll-like receptors (TLR4), P-$I{\kappa}B{\alpha}$ and nuclear factor-${\kappa}B$ p65(NF-${\kappa}B$ P65) in ileum compared to the HH group. This study suggested that vitamin E protectis from intestinal injury caused by high altitude hypoxia environment. These effects may be related to the HIF and TLR4/NF-${\kappa}B$ signaling pathway.

  • https://doi.org/10.4196/kjpp.2014.18.4.313 인용 PDF KSCI

FIXED POINTS OF A CERTAIN CLASS OF ASYMPTOTICALLY REGULAR MAPPINGS

  • Jung, Jong-Soo;Thakur, Balwant-Singh;Sahu, Daya-Ram
    • 대한수학회보
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    • 제37권4호
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    • pp.729-741
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    • 2000

  • In this paper, we study in Banach spaces the existence of fixed points of asymptotically regular mapping T satisfying: for each x, y in the domain and for n=1, 2,…, $$\parallelT^nx-T^ny\parallel\leq$\leq$a_n\parallelx-y\parallel+b_n (\parallelx-T^nx\parallel+\parallely-T^ny\parallely)$$ where $a_n,\; b_n,\; C_n$ are nonnegative constants satisfying certain conditions. We also establish some fixed point theorems for these mappings in a Hibert space, in L(sup)p spaces, in Hardy space H(sup)p, and in Soboleve space $H^{k,p} for 1<\rho<\infty \; and \; k\geq0$. We extend results from papers [10], [11], and others.

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INVARIANT DIFFERENTIAL OPERATORS ON THE MINKOWSKI-EUCLID SPACE

  • Yang, Jae-Hyun
    • 대한수학회지
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    • 제50권2호
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    • pp.275-306
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    • 2013

  • For two positive integers $m$ and $n$, let $\mathcal{P}_n$ be the open convex cone in $\mathbb{R}^{n(n+1)/2}$ consisting of positive definite $n{\times}n$ real symmetric matrices and let $\mathbb{R}^{(m,n)}$ be the set of all $m{\times}n$ real matrices. In this paper, we investigate differential operators on the non-reductive homogeneous space $\mathcal{P}_n{\times}\mathbb{R}^{(m,n)}$ that are invariant under the natural action of the semidirect product group $GL(n,\mathbb{R}){\times}\mathbb{R}^{(m,n)}$ on the Minkowski-Euclid space $\mathcal{P}_n{\times}\mathbb{R}^{(m,n)}$. These invariant differential operators play an important role in the theory of automorphic forms on $GL(n,\mathbb{R}){\times}\mathbb{R}^{(m,n)}$ generalizing that of automorphic forms on $GL(n,\mathbb{R})$.

  • https://doi.org/10.4134/JKMS.2013.50.2.275 인용 PDF KSCI

MATRIX OPERATORS ON FUNCTION-VALUED FUNCTION SPACES

  • Ong, Sing-Cheong;Rakbud, Jitti;Wootijirattikal, Titarii
    • Korean Journal of Mathematics
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    • 제27권2호
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    • pp.375-415
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    • 2019

  • We study spaces of continuous-function-valued functions that have the property that composition with evaluation functionals induce $weak^*$ to norm continuous maps to ${\ell}^p$ space ($p{\in}(1,\;{\infty})$). Versions of $H{\ddot{o}}lder^{\prime}s$ inequality and Riesz representation theorem are proved to hold on these spaces. We prove a version of Dixmier's theorem for spaces of function-valued matrix operators on these spaces, and an analogue of the trace formula for operators on Hilbert spaces. When the function space is taken to be the complex field, the spaces are just the ${\ell}^p$ spaces and the well-known classical theorems follow from our results.

  • https://doi.org/10.11568/kjm.2019.27.2.375 인용 PDF KSCI

탐색적 방법에 의한 건축공간 배치계획 최적화에 대한 고찰 (A Study on the Optimized Architectural Space Planning by Searching Algorithm Method)

  • 임명구;김수영
    • 한국디지털건축인테리어학회논문집
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    • 제1권1호
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    • pp.51-58
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    • 2001

  • The purpose of this study is to improve productivity of architectural space planning(A.S.P,) by computer system and to optimize ASP. A searching algorithm is the best way to slave optimized A.S.P. Because architectural design is too many various site situations and client's demands to specify the general solving methods. This method seek the best design case in all possibility and to be modeled as this; $\rightarrow$[$\rightarrow$$\rightarrow$