Wyniki wyszukiwania - Biblioteka Nauki

1

Development of a height-adjustable manhole

100%

Kim C. H. , Park J. H.

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2006

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tom Vol. 14, nr 1-2

21--25

EN

Purpose: It is found that to determine optimal dimension of gear-shaped parts through bending stress formulas and Taguchi orthogonal array table. Design/methodology/approach: Whole parts of real manhole were manufactured experimentally by casting nodular graphite cast iron according to the Korean Standard. It can be used as water supply and drainage, sewage, telecommunication cable, traffic sign, electricity supply, etc. with better performance. Findings: This manhole consists of cover, outer cylinder and inner cylinder. The gear-shaped stairs are extruded on the outer wall of inner cylinder, and on the inner wall of outer cylinder. The outer cylinder has three columns of 4~5 receptacles, and the inner cylinder has three columns of 6~7 protrusions. The inner cylinder shall be slided into the outer cylinder and then be rotated within the outer cylinder in order to lock the protrusions into the receptacles. The stairs on outer cylinder and inner cylinder allow workers to control the height of manhole because the height is controlled by adequate locking them on sidewall in installation or rehabilitation of manholes. It is designed for the perfect lock. Practical implications: Use of this manhole must be drastically economical because it requires only 1-2 workers and simple adjustment of the height comparing with that the existing manholes is required 4-5 workers and reconstruction because conventional should be entirely excavated to reinstall or repair. This entire excavation of a manhole causes too much time-consuming work, waste of resources, and obstruction of traffic. Originality/value: This paper describes an optimal design of manhole, which deals with design elements of manhole which has gear-shaped stairs on the road to adjust its height.

2

Intuitionistic Fuzzy Optimized Weighted Geometric Bonferroni Means and Their Applications in Group Decision Making

80%

Park J. H. , Kim J. Y. , Kwun Y. C.

Fundamenta Informaticae

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2016

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tom Vol. 144, nr 3/4

363--381

EN

The geometric Bonferroni mean (GBM) is an important aggregation technique which reflects the correlations of aggregated arguments. Based on the GBM, in this paper, we develop the optimized weighted geometric Bonferroni mean (OWGBM) and the generalized optimized weighted geometric Bonferroni mean (GOWGBM), whose characteristics are to reflect the preference and interrelationship of the aggregated arguments. Furthermore, we develop the intuitionistic fuzzy optimized weighted geometric Bonferroni mean (IFOWGBM) and the generalized intuitionistic fuzzy optimized weighted geometric Bonferroni mean (GIFOWGBM), and study their desirable properties such as idempotency, commutativity, monotonicity and boundedness. Finally, based on the IFOWGBM and GIFOWGBM, we present an approach to multi-criteria decision making and illustrate it with a practical example.

3

Structural performance of rectangular section confined by squared spirals with no longitudinal bars influencing the confinement

70%

Lee J. M. , Kim Y. S. , Kim S. W. , Park J. H. , Kim K. H.

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2016

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tom Vol. 16, no. 4

795--804

EN

Structural performance of rectangular concrete section confined by squared spirals was investigated. Through the uni-axial compression test using concrete prisms with squared spirals and without longitudinal bars, the enhancement of strength and deformation capacity of rectangular concrete section was scrutinized. By the experimental observations on the properties of lateral expansion of concrete prism, a moment of reaching the axial peak stress in section was predicted in a good accuracy. Qualitative relationships between the structural performance (the enhancement of strength and deformation capacity) of concrete prism and confinement efficiency were studied. Also, for the effective use of normal- and high-strength lateral reinforcement, a design implication using the qualitative relationship of the tensile stress in lateral reinforcement at failure of concrete prism with parameters was proposed.

4

Enhanced Microwave Absorption of CNT Composites Mixing with Fe3O4 and Carbonyl Iron

61%

Park J. H. , Choi J. , Lee K. , Park J. , Song J. K. , Jeon E.

Archives of Metallurgy and Materials

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2018

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tom Vol. 63, iss. 3

1513--1516

EN

We fabricated two different kinds of composite materials for absorbing microwave in a frequency range of 2 to 18 GHz using coaxial airline and thru-reflect-line (TRL) method. The composite materials having carbon nanotube (CNT) with carbonyl iron (CI) or iron oxide (Fe3 O4 ) were fabricated by mixing each components. Magnetic properties were measured by SQUID equipment. Complex permittivity and complex permeability were also obtained by measuring S-parameters of the toroidal specimen dispersing CI/CNT and Fe3 O4 /CNT into the 50 weight percent (wt%) epoxy resin. The real permittivity was improved by mixing the CNT however, the real permeability was same as pure magnetic powders. The CI/CNT had a maximum value of real permittivity and real permeability, 11 and 1.4 at 10 GHz, respectively. The CNT composites can be adapted to the radar absorbing materials, band width 8-12 GHz.

5

Fabrication of Mo-Si-B Intermetallic Compound Powders Under Different Heat Treatment Conditions

61%

Park J. H. , Lee S. , Kim D. , Kim Y. , Yang S. H. , Lee S. H.

Archives of Metallurgy and Materials

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2018

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tom Vol. 63, iss. 3

1509--1512

EN

In this research, we investigated the effects of reduction atmospheres on the creation of the Mo-Si-B intermetallic compounds (IMC) during the heat treatments. For outstanding anti-oxidation and elevated mechanical strength at the ultrahigh temperature, we fabricated the uniformly dispersed IMC powders such as Mo5SiB2 (T2) and Mo3Si (A15) phases using the two steps of chemical reactions. Especially, in the second procedure, we studied the influence of the atmospheres (e.g. vacuum, argon, and hydrogen) on the synthesis of IMCs during the reduction. Furthermore, the newly produced IMCs were observed by SEM, XRD, and EDS to identify the phase of the compounds. We also calculated an amount of IMCs in the reduced powders depending on the atmosphere using the Reitveld refinement method. Consequently, it is found that hydrogen atmosphere was suitable for fabrication of IMC without other IMC phases.

6

Proteomic analysis of tumor tissue in CT-26 implanted BALB/C mouse after treatment with ascorbic acid

61%

Lee J. , Lee G. , Park J. H. , Lee S. , Yeom C.-H. , Na B. , Park S.

Cellular and Molecular Biology Letters

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2012

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tom 17

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nr 1

EN

Tumor establishment and penetration consists of a series of complex processes involving multiple changes in gene expression and protein modification. Proteome changes of tumor tissue were investigated after intraperitoneal administration of a high concentration of ascorbic acid in BALB/C mice implanted with CT-26 cancer cells using two-dimensional gel electrophoresis and mass spectrometry. Eighteen protein spots were identified whose expression was different between control and ascorbic acid treatment groups. In particular, eukaryotic translation initiation factor 3 subunit 1, nucleophosmin, latexin, actin-related protein 2/3 complex subunit 5, M2-type pyruvate kinase, vimentin, tumor protein translationally-controlled 1, RAS oncogene family Ran, plastin 3 precursor, ATPase, Rho GDT dissociation inhibitor β, and proteasome activator subunit 2 expression were quantitatively up-regulated. The increase in the level of these proteins was accompanied by an increase in mRNA level. The cytoskeleton protein actin, vimentin, and tumor protein translationally-controlled 1 showed quantitative expression profile differences. A change in actin cytoskeleton distribution, functionally relevant to the proteome result, was observed after treatment with ascorbic acid. These results suggest a previously undefined role of ascorbic acid in the regulation of cytoskeleton remodeling in tumor tissues.

7

Ambivalent role of gallated catechins in glucose tolerance in humans: A novel insight into non-absorbable gallated catechin-derived inhibitors of glucose absorption

51%

Park J. H. , Jin J. Y. , Baek W. K. , Park S. H. , Sung H. Y. , Kim Y. K. , Lee J. , Song D. K.

Journal of Physiology and Pharmacology

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2009

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tom 60

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nr 4

101-109

EN

Prolonged postprandial hyperglycemia is a detrimental factor for type 2 diabetes and obesity. The benefit of green tea extract (GTE) consumption still requires confirmation. We report the effects of circulating green tea catechins on blood glucose and insulin levels. Oral glucose loading 1 h after GTE ingestion in humans led to higher blood glucose and insulin levels than in control subjects. Gallated catechins were required for these effects, although within the intestinal lumen they have been known to decrease glucose and cholesterol absorption. Treatment with epigallocatechin-3-gallate hindered 2-deoxyglucose uptake into liver, fat, pancreatic beta-cell, and skeletal muscle cell lines. The glucose intolerance was ameliorated by gallated catechin-deficient GTE or GTE mixed with polyethylene glycol, which was used as an inhibitor of intestinal absorption of gallated catechins. These findings may suggest that the gallated catechin when it is in the circulation elevates blood glucose level by blocking normal glucose uptake into the tissues, resulting in secondary hyperinsulinemia, whereas it decreases glucose entry into the circulation when they are inside the intestinal lumen. These findings encourage the development of non-absorbable derivatives of gallated catechins for preventative treatment of type 2 diabetes and obesity, which would specifically induce only the positive luminal effect.