• Journal of Advanced Marine Engineering and Technology
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• v.38 no.6
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• pp.698-703
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• 2014

Currently, demand of liquefied natural gas as an alternatice energy inceases because of depletion of fossil fuels. it is accompanied by inceasing demand of LNG ship. Consequentially, it is expected that demand of bellows for LNG ship increase. The material used for LNG vessels's bellows is an alloy of INCOLOY 825 and STS316L, which are strong against low-temperature brittleness and seawater corrosion. This study establishes the welding condition of LNG vessel's bellows material in extremely low temperature, and analyzes the formability of weld through Erichsen Test. When welding was conducted at optimal condition, tensile strength of weld presneted strength value up to 90% compared with base metal. As results of formalbility through Erichsen test, very good weld that failure occrued in base metal was gotten.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.2
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• pp.80-85
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• 2021

In the fourth industrial revolution, the demand for metal three-dimensional (3D) printing technology is rapidly increasing. Metal 3D printing is an efficient method for manufacturing products because the method reduces material waste compared to subtractive manufacturing. In addition, products with complex shapes, such as turbine blades, can be easily produced using metal 3D printing because the method offers a high degree of freedom. However, due to the long production time of metal 3D printing, mass production is impossible, and post-processing is necessary due to its low precision. Therefore, it is necessary to develop a new hybrid process that can efficiently process metals and to develop a metal 3D-printing-based hybrid processing system technology to secure high processing precision and manufacture complex shapes. In this study, the structural stability of a metal 3D printer based hybrid machining center was analyzed through structural analysis before its development. In addition, we proposed a design modification that can reduce the weight and increase the stiffness of the hybrid machining center by performing shape lightning based on the structural analysis results.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.12
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• pp.996-1001
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• 2010

Recently, the demand of ceramic metal halide lamp has been expanded. Therefore, the lamp with high efficiency and long lifetime are increasing and the evaluation of reliability is needed. In this paper, the degradation phenomena of ceramic metal halide lamp was studied. The lamp was tested for 3000 on/off cycles with each cycle having a duration of 20 minutes on and 20 minutes off based on the accelerated aging experiment based on "Reliability Standards RS C 0085". As result, the corrosion of arc tube and leak was appeared from reaction between inner wall of PCA and chemical elements, and distortion of electrode was resulted from difference of thermal expansion between arc tube of PCA and electrode. Also, the efficiency of lamp was decreased by the change of inner pressure, operation temperature, and driving voltage from wall blackening.

• Korean Institute of Interior Design Journal
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• no.17
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• pp.120-127
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• 1998

Because of the advancements of these modern tecniques and new materials being developed expressionally diverse methods of utilizing metal and glass are being discovered. modern architects in order to add an open-hearted and homogeneous concept into their endeavors to create a transparent space are inclining to the many expressive characteristics which glass and metal provide. Furthermore the products of these endeavors are bringing forth various key elements in respect to useage for today's interior spaces, Due to differing methods of setting up the interior sphere is fastly becoming more generous than viewpoints of the past. Through the use of organization moreover from the former geometric school of thought curvilinear and active organization/ expressive inclinations are becoming diversified. Thus in accordance with the diversifying methods of fixing glass for a sleek and reflective exterior and due to the influence of durability to these fixtures precision not just decoration is gradually becoming more in demand/ Hereupon this study enlightens from the standpoint of planninf for interior spaces through the utilization of glass and metal upon the key factors of expressive attributes and the possibilities which thusly arise. The purpose of this study is to apply these theories to an actual case model study and verify their validity.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.121-126
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• 2000

Metal/Ceramic structures have many attractive properties, with great potential for applications that demand high stiffness, as well as chemical and biological stability, thermal and electrical insulation. They are currently in use for mechanical and thermal protection in cutting tool and engine parts. With all their great advantage, ceramics suffer from one major problem they are brittle, and are especially susceptible to cracking from surface contacts. Delamination at the interfaces with adjacent layers is a particularly disturbing problem, and can cause premature failure of a composite system. so determination of adhesive properties of coating is one of the most important problems for the extension of the use of coated materials. In this work, mechanical characteristics of Interface of ceramic/Metal composites are evaluated by means of hardness test, indentation test apparent interfacial toughness and bonding strength test. The interface indentation test provides a relation between the applied load(P) and the length of the crack(a) created at the interface between the coating and the substrate.

• Resources Recycling
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• v.7 no.3
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• pp.42-51
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• 1998

Hydrogen in atmosphere can easily dissolve in melt of light metal alloys. Increasing demand for recycling of light metal a alloys has, therefore, focused attention on the removal of hydrogen gas, and alloy addition in melt has become an imporLant r refining process. For this purpose behaviors of mixing and hydrogen degassing in impeller agitated refming vessel with/without barnes were investigated. Flow patterns, mixing time behavior and kinetics of degassing in various agitating conditions were analysed in watet model experiments. And, numerical analysis on turbulent flow pattern in impeller agitated vessels was performed.

• Journal of the Korea Furniture Society
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• v.23 no.2
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• pp.110-121
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• 2012

With people's recent increasing interest in good design products, wood and metal products have gained great popularity. However, it was believed that it would be necessary to have a transformation to the manufacturing method based on digital data and equipments from existing analog-based manufacturing method, in order to meet consumers' demand. This study was aimed to seek for the possibility of mass-producing wood and metal products through the research on the type, usage and development conditions of digital data and the methods of utilizing digital equipments. As for research methods, the study analyzed the concepts and types of digital data through various internet and literature reviews and suggested perpetual calendar products as the final outcome of design development using computer data. Through this, the study summarized and organized actual design development processes by stage to provide basic data that could become the foundation of research on the design of wood and metal products using digital data. Through the outcome of this project, the following effects could be expected by developing wood and metal products through digital data. First, its accurate and precise process would help mass-produce complex forms of products and reduce their defective rate. Second, the compatible production of various types of digital equipments would lead to a cost reduction. Third, the diversity of design could be pursued by overcoming technical limitations. In order to satisfy the above expectation effects, such as realization of developing and producing various wood and metal products, there should be designers' creative experimental spirits, their active information exchange and cooperation with the companies concerned.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.217-217
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• 2011

Recently, demand for thermally stable metal nanoparticles suitable for chemical reactions at high temperatures has increased to the point to require a solution to nanoparticle coalescence. Thermal stability of metal nanoparticles can be achieved by adopting core-shell models and encapsulating supported metal nanoparticles with mesoporous oxides [1,2]. However, to understand the role of metal-support interactions on catalytic activity and for surface analysis of complex structures, we developed a novel catalyst design by coating an ultra-thin layer of titania on Pt supported silica ($SiO_2/Pt@TiO_2$). This structure provides higher metal dispersion (~52% Pt/silica), high thermal stability (~600$^{\circ}C$) and maximization of the interaction between Pt and titania. The high thermal stability of $SiO_2/Pt@TiO_2$ enabled the investigation of CO oxidation studies at high temperatures, including ignition behavior, which is otherwise not possible on bare Pt nanoparticles due to sintering [3]. It was found that this hybrid catalyst exhibited a lower activation energy for CO oxidation because of the metal-support interaction. The concept of an ultra-thin active metal oxide coating on supported nanoparticles opens-up new avenues for synthesis of various hybrid nanocatalysts with combinations of different metals and oxides to investigate important model reactions at high-temperatures and in industrial reactions.

• Journal of Powder Materials
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• v.26 no.4
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• pp.345-349
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• 2019

With increasing demand for resources worldwide, Korea has been negotiating with resource-holding countries to achieve conservation of energy resources. Among them, Russia is the third largest resource-producing and exporting nation in the world and has several resource materials such as nickel, platinum group metals, gold, and other reserves. As a result, there is growing interest in cooperation between Korea and Russia. The aim of this article is to summarize the current status of market flow of Russian energy resources as well as Russia's economic cooperation with Korea. Notably, South Korea needs to focus on investing in overseas mines for a stable supply of rare metals. Nevertheless, securing rare metals is a major task by understanding the flow and policy direction of Russian material mines.

• Korean Journal of Materials Research
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• v.32 no.2
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• pp.98-106
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• 2022

Metal-organic frameworks (MOFs) are widely used in various fields because they make it easy to control porous structures according to combinations of metal ions and organic linkers. In addition, ZIF (zeolitic imidazolate framework), a type of MOF, is made up of transition metal ions such as Co²⁺ or Zn²⁺ and linkers such as imidazole or imidazole derivatives. ZIF-67, composed of Co²⁺ and 2-methyl imidazole, exhibits both chemical stability and catalytic activity. Recently, due to increasing need for energy technology and carbon-neutral policies, catalysis applications have attracted tremendous research attention. Moreover, demand is increasing for material development in the electrocatalytic water splitting and metal-air battery fields; there is also a need for bifunctional catalysts capable of both oxidation/reduction reactions. This review summarizes recent progress of bifunctional catalysts for electrocatalytic water splitting and metal-air batteries using ZIF-67. In particular, the field is classified into areas of thermal decomposition, introduction of heterogeneous elements, and complex formation with carbon-based materials or polyacrylonitrile. This review also focuses on synthetic methods and performance evaluation.