• Korean Journal of Materials Research
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• v.14 no.8
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• pp.579-586
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• 2004

A study on the effects of oxide growth on the mechanical properties degradation of pure zirconium and Zircaloy-4 is carried out with high temperature tensile tests. It is found that the mechanical properties can deteriorate with the oxide growth less than $1\%$ of total specimen cross section, especially at $300\~400^{\circ}C$ that is zirconium alloy cladding temperature during the nuclear reactor operation. It is also revealed that Young's modulus changes little but yield strength and tensile strength drop down to $20\% and 40\%$ of the room temperature strength, respectively, in the temperature range. Fractographic analysis shows that the number of dimples decreases and fractured surface becomes smooth with increasing oxide thickness.

• The Mathematical Education
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• v.45 no.1 s.112
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• pp.61-74
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• 2006

The ability of understanding the number and number systems, grasping the properties of number systems, and manipulating number systems is the foundation to understand algebra. It is useful to deepen students' mathematical understanding of number systems and operations. The authentic understanding of numbers and operations can make it possible for the students to manipulate algebraic symbols, to represent relationship among sets of numbers, and to use variables to investigate the properties of sets of numbers. The high school students need to understand the number systems from more abstract perspective. The purpose of this study is to study on understanding and application ability of eleventh graders of basic properties of operations with real numbers.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05c
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• pp.36-40
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• 2002

This paper presents the results of a investigation, a development of the measuring system for grounding properties in live-line. The importance of the grounding system and it's property has been increased with the development, enlarge in capacity, of electrical industry. Moreover, with the rapid growth of communication and precision industry, now, we should consider the grounding properties to ensure the stable and/or safe operation. But the conventional measuring system is not proper to measure the grounding properties of the system, voltage applied. So, in this investigation, we proposed a new method for live-line measurement and develope the system. And through the field test we could confirm the superior performance of th developed system.

• Journal of Energy Engineering
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• v.24 no.2
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• pp.79-83
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• 2015

Hydrogen has long been recognized as a fuel having some unique and highly desirable properties, for application as a fuel in engines. Hydrogen has some remarkably high values of the key properties for transport processes, such as kinematic viscosity, thermal conductivity and diffusion coefficient, in comparison to those of the other fuels. Such differences together with its extremely low density and low luminosity help to give hydrogen its unique diffusive and heat transfer characteristics. The thermodynamic and heat transfer characteristics of hydrogen tend to produce high compression temperatures that contribute to improvements in engine efficiency and lean mixture operation.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.731-736
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• 2006

Groundwater heat pump (GWHP) system has been expected to achieve the higher coefficient of performance (COP) and more energy-saving than the conventional air-source heat pump (ASHP) system. Its performance significantly depends on the characteristics of groundwater and the underground thermal properties. Furthermore, there is a large difference of COP in utilizing groundwater between as a heat resource and as a thermal storage medium. For properties of groundwater there is suitable utilizing system. However, many of GWHP systems have not been considered sufficiently such properties. This research describes optimization of GWHP system according to the properties of groundwater based on 3D numerical heat and water transport simulation.

• Korean Journal of Heritage: History & Science
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• v.38
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• pp.421-474
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• 2005

The Cultural Heritage Committee is an advisory committee established under the Cultural Heritage Administration with the aim of carrying out examination and deliberation on preservation, management and use of cultural properties. The Cultural Heritage Administration is responsible for Korean cultural properties. It was found to produce and execute policies on cultural properties, which involves in-depth investigation and consultation of experts in the fields of cultural properties. In here the Cultural Heritage Committee plays an important role in policy-making on Korean cultural properties. Governmental committees in Korea are largely divided into consultation committees and administrative commissions. Consultation committees are subdivided into consultation, deliberation and legislative committees. The Korean government established the Bureau of Cultural Properties in October 1961, and enacted provisions (as a presidential decree) on March 27, 1962, by the Cultural Properties Act, January 10, 1962. The Cultural Heritage Committee was opened as a deliberation committee which covers the entirety of cultural properties, including designation and cancellation of cultural properties, on which currently 120 members serve in 9 subcommittees. The committee member hold two years membership. This analysis contains a frame and scheme of the committee, function and statue of the current operation and study on role of a deliberation committee.

• Communications of the Korean Mathematical Society
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• v.24 no.3
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• pp.321-331
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• 2009

In this paper, we investigate some fundamental properties and establish some results of f-derivations of BCI-algebras. Also, we prove Der(X), the collection of all f-derivations, form a semigroup under certain binary operation.

• Journal of the Korean Data and Information Science Society
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• v.13 no.2
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• pp.209-216
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• 2002

In this paper, we introduce a concept of (H)-property which generalize that of increasing(decreasing) property of binary operation. We also treat some works related to operations on fuzzy numbers and generalize earlier results of Kawaguchi and Da-te(1994).

• Proceedings of the Korea Society of Design Studies Conference
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• 2001.10a
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• pp.75-75
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• 2001

• Journal of the Chungcheong Mathematical Society
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• v.30 no.4
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• pp.357-367
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• 2017

In this paper, we introduce the notion of multiplier of AC-algebra and consider the properties of multipliers in AC-algebras. Also, we characterized the fixed set $Fix_d(X)$ by multipliers. Moreover, we prove that M(X), the collection of all multipliers of AC-algebras, form a semigroup under certain binary operation.