• Nonlinear Functional Analysis and Applications
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• 제29권3호
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• pp.673-710
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• 2024

In this paper, we propose a modified Halpern's iterative scheme developed from a sequence of a new class of enriched nonspreading mappings and an enriched nonexpansive mapping in the setup of a real Hilbert space. Moreover, we prove strong convergence theorem of the proposed method under mild conditions on the control parameters. Also, we obtain some basic properties of our new class of enriched nonspreading mappings.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2005년도 춘계 학술기술논문발표대회 논문집
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• pp.69-72
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• 2005

Recently, there have been many studies seeking towards the utilization of cementitious powder from concrete waste as recycle cement. However, most of the studies actually have been researches about the reuse of mortar or paste, not concrete waste. In fact, either mortar or paste is quite different from a real concrete waste in terms of age and mixture. Thus the purpose of this study is to examine basic physical properties of recycle cement, manufactured with cementitious powder from concrete waste, and analyze differences in chemical and hydraulic properties of the cement and its tested model. As a result of the chemicai analysis, recycle cement is composed mainly of CaO and SiO2, and that it is even lower in the content of CaO than Portland cement, which is also supported by previous studies. But, Differently from previous studies, plastic working at the temperature of 650 was found an optimal condition under which cementitious powder from concrete waste could restore its hydraulic properties.

• 한국화재소방학회:학술대회논문집
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• 한국화재소방학회 2008년도 추계학술논문발표회 논문집
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• pp.262-269
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• 2008

Chemical products have had an favorable influence on our everyday life, and contributed very much to the development of human culture. According to the rapid change of industry and the development of scientific technique the using chemical products are increasing more and more. Chemical products can have any hazardous property such as flammability or explosiveness. There are occurring many accidents in the international trade due to the different classification and labelling of chemicals produced in various countries. The main purpose of this work is the development of global standard test methods for the chemicals, and the classification and labelling in building block approach by means of the basic technical data. Oxidizing solids, combustible solids, spontaneously combustible materials, water-prohibitive materials, flammable liquids, self-reactive materials and oxidizing liquids have been tested. The results have been classified according to the hazard material safety regulation and the UN regulation, and summarized in a data-base.

• Nuclear Engineering and Technology
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• 제44권3호
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• pp.331-342
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• 2012

Since the opening of the Shin-Kori #1,2 in 2005, fly ash mixed concrete has been used for NPP concrete structures under construction in Korea with the aim of preventing aging and improving durability. In this paper, the quality suitability of fly ash manufactured in Korea is assessed and the basic physical properties of fly ash mixed concrete and its durability against primary causes of aging are verified through experimental methods. Because of the internal structure filling effect from the pozzolanic reaction of fly ash and the resulting improvements in mechanical performance in such areas as strength and salt damage resistance, the durability of fly ash mixed concrete is shown to be superior. It is judged that this result can be applied in measures not only for improving the safety of NPP structures in operation in Korea but also for implementing effective structure life management should extending the life of structures be needed in the future.

• 한국가구학회지
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• 제10권1호
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• pp.57-63
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• 1999

This study was carried out to analyze the relationship between basic physical properties and acoustical characteristics of imported violin wood and to offer the information on raw material procurement and incoming-material quality control to domestic violin makers which have purchased most raw materials from European exporting countries at high expense. Equilibrium moisture content of European spruce with lower specific gravity after the prolonged storage was rather higher than that of European maple with higher specific gravity. The specific gravity of spruce increased with decreasing annual ring width, however, that of narrower annual ring. Increasement in specific gravity enhanced the dynamic Young's modulus of both wood species, but influenced the vibration energy loss by internal friction differently between two species. For dynamic MOE, qurater-sawn spruce was higher than the flat-sawn, but maple showed the reverse directional characteristics. Consequently, it would be well for violin makers to establish the standard for materials and quality control system to assure the quality of their violin products.

• 대한토목학회논문집
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• 제9권2호
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• pp.55-61
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• 1989

본 연구에서는 전기로슬래그를 잔골재로 사용하기 위한 기초단계로서 전기로슬래그의 화학성분, 조성광물 및 물리적성질에 대하여 고찰하였으며, 전기로슬래그의 팽창기구(膨脹機構), 안정화방안(安定化方案)에 대하여 검토하였다. 그리고 안정화된 전기로슬래그를 잔골재의 일부와 대체한 콘크리트의 기초적 성질을 알아보기 위하여 실시한 실험결과에 대해서도 고찰하였다.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2002년도 제24회 KOSCO SYMPOSIUM 논문집
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• pp.212-219
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• 2002

Waste fuels, which originate from different sources, have unique combustion characteristics. The characteristics should be considered in applying FBC(fluidized bed combustor) technology to those fuels. The effects of fuel properties and operating conditions on FBC reactivity were investigated by means of carbon based parameter called mean carbon conversion time, rate of carbon conversion, fraction of carbon conversion and carbon recovery. And the basic physical and chemical mechanisms taking place in a fluidized bed were summarized. Major parameters in designing and operating FBC were evaluated in terms of the fuel properties and the combustion environment.

• 통합자연과학논문집
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• 제4권3호
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• pp.182-186
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• 2011

Chemical modification of porous silicon surface has been investigated to have different physical surface properties. Porous silicon modified with dodecyl functionality exhibits hydrophobic feature, however the oxidation of porous silicon to modify with hydroxyl group displays hydrophilic properties. Surface characterization for both dodecyl and hydroxyl derivatized porous silicon was investigated by FT-IR spectroscopy. To determine the surface coverage, the amine functionalized surface was reduced by dithiothreitol (DTT) and the released 2-thiopyridone was quantified by UV/vis spectroscopy.

• 통합자연과학논문집
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• 제4권3호
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• pp.187-191
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• 2011

The differences of properties for both single-layered and multi-layered porous silicon were investigated. Multistructured porous silicons such as DBR or rugate porous silicon exhibit strong reflection resonances providing the reflection of a specific wavelength in the optical reflectivity spectrum. DBR PSi displays a square varying porosity gradient in the direction perpendicular to the plane of the filter but a sinusoidally varying porosity gradient was obtained for rugate PSi.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2014년도 춘계 학술논문 발표대회
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• pp.208-209
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• 2014

Recently, many environmental problems occur due to the waste shells in South Korea. In case of oyster and cockle, utilizing waste shells to produce fertilizer once also, but due to sluggish consumption, production is no longer difficult. The stored amount of waste shells in the fertilizer manufacturing company is overfilled, and thus cannot accept any more of the waste shells. As a result, landfill and dumping of waste shells have become an increasingly environmental problems. In this research, the basic physical properties and interfacial bonding form of the mortar mixed with waste shells (manila clam, cockle, clam, sea mussel, oyster) were evaluated.