• Computers and Concrete
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• v.9 no.4
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• pp.293-310
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• 2012

This paper discusses a new constitutive model called the high-rate brittle microplane (HRBM) model and also presents the details of a new software package called the Virtual Materials Laboratory (VML). The VML software package was developed to address the challenges of fitting complex material models such as the HRBM model to material property test data and to study the behavior of those models under a wide variety of stress- and strain-paths. VML employs Continuous Evolutionary Algorithms (CEA) in conjunction with gradient search methods to create automatic fitting algorithms to determine constitutive model parameters. The VML code is used to fit the new HRBM model to a well-characterized conventional strength concrete called WES5000. Finally, the ability of the new HRBM model to provide high-fidelity simulations of material property experiments is demonstrated by comparing HRBM simulations to laboratory material property data.

• Nuclear Engineering and Technology
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• v.52 no.4
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• pp.797-801
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• 2020

Most of irradiated graphite that should be disposed comes from moderators and reflectors of nuclear power plants. The quantity of irradiated graphite could be higher in the future if high-temperature reactors (HTRs) will be deployed. In this case noteworthy quantities of fuel pebbles containing semi-graphitic carbonaceous material should be added to the already existing 250,000 tons of irradiated graphite. Industry graphite is largely used in industrial applications for its high thermal and electrical conductivity and thermal and chemical resistance, making it a valuable material. Irradiated graphite constitutes a waste management challenge owing to the presence of long-lived radionuclides, such as ¹⁴C and ³⁶Cl. In the ENEA Nuclear Material Characterization Laboratory it has been successfully designed a procedure based on the exfoliation process organic solvent assisted, with the purpose of investigate the possibility of achieving graphite significantly less toxic that could be recycled for other purpose [1]. The objective of this paper is to evaluate the possibility of the scalability from laboratory to industrial dimensions of the exfoliation process and provide the prototype of a chemical plant for the treatment of irradiated graphite.

• Bulletin of the Korean Chemical Society
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• v.20 no.5
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• pp.517-524
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• 1999

By heating the magnesiumsilicate (Mg2SiO4:forsterite) xerogel in carbon dioxide, carbonaceous component was intentionally introduced into the amorphous solid precursor. Carbon was introduced homogeneously as unidentate carbonate. Upon being heated at 800 。C in carbon dioxide, the xerogel which had homogeneously distributed carbonaceous component in it crystallized into a single phase product of a new crystalline material, which had approximate composition of Mg8Si4Ol8C. The powder X-ray diffraction pattern of the new crystalline material did not match with any known crystalline compound registered in the powder diffraction file. Crystallization from amorphous xeroget to the new crystalline phase occurred in a very narrow range of temperature, from 750 。C to 850 。C in carbon dioxide, or in dty oxygen. Upon being heated above 850 。C, carbonaceous component was expelled from the product, accompanied by irreversible transition from the new crystalline material to forsterite.

• Korean Institute of Interior Design Journal
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• no.38
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• pp.100-107
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• 2003

The space can recognize by experience of sense, the each space to make identity through this. The contemporary architecture make possible an experience of sense through a complex paradigm and a composite concept expression. The material is not the assist to make a form, but to induce an image and an emotion of designers. The new material make possible the different design expression and the new aesthetic value. The appearance of difference material means the possibility to realize a designer's concept. The purpose of the study Is to analyze the new possibility of material expression through the study on material expression of interior design to associate the sense of being alive, to use basic data of the relation the material and the creativity. The study range is to define the sense of being alive, to image expression of material. It is to analyze the expression method of materials through to analyze the contemporary interior design. The expression method of materials to image the sense of being alive is direct and indirect and compromise. The interior design is visually to realize designer's concept, and the interior designer has to realize their it. The later study is on detail of material, in order to realize of material.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.705-710
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• 2002

Welding is used not only during the shipbuilding, but also during the repairing of ships. While repairing of ships, it is inevitable to weld new materials with degraded materials. In this case, it is predicted that the strength of both the sections is not identical each other. In this study, the respective welded joints in terms of mechanical properties such as microstructure, mechanical strength and fatigue crack propagation, with the component obtained from the barge used for a long-term period, were analyzed. It was found that the material degradation had a significant effect on the welded joints. The fatigue crack propagation in welded sections showed a big difference. The rate of fatigue crack growth of degraded material for both heat affected zone and parent metal was faster than that of new material. By contrast, The result within identical materials showed that the heat-affected zone was slower than that of parent metal

• Journal of the Korean Society for Precision Engineering
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• v.19 no.11
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• pp.75-82
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• 2002

Welding is used not only for the shipbuilding, but also for the repairing of ships. While repairing of ships, it is inevitable to weld new materials with degraded materials. In this case, it is predicted that the strength of both the sections is not identical each other. In this study, the respective welded joints in terms of mechanical properties such as microstructure, mechanical strength and fatigue crack propagation, with the component obtained from the barge used for a long-term period, were analyzed. It was found that the material degradation had a significant effect on the welded joints. The fatigue crack propagation in welded sections showed a big difference. The rate of fatigue crack growth of degraded material for both heat affected zone and parent metal was faster than that of new material. By contrast, the result from identical materials showed that the rate of fatigue crack growth of the heat-affected zone was slower than that of parent metal.

• Nuclear Engineering and Technology
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• v.38 no.5
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• pp.437-442
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• 2006

European Material Test Reactors (MTRs) have provided essential support for nuclear power programs over the last 40 years. MTRs are now ageing in Europe and they cannot ensure the securing of experimental capability for the next decades. In this context, a new Material Testing Reactor, named Jules Horowitz Reactor -JHR-, operated as an international user-facility, is under development in Europe. The European MTRs context and the JHR objectives and status will be presented. Emphasis will be put on experiments in the field of nuclear fuels and materials irradiation which are developed in the framework of European and international collaboration.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.441-443
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• 2005

According as CCFL(Cold Cathode Fluorescent lamp) of light source in Backlight unit for Note PC (Personal computer) is presently needed to low power consumption and long life time, the development focus of CCFL is going on the discharge gas, phosphor and electrode material. First of all, discharge voltage characteristic of CCFL is closely connected with electrode material For low discharge voltage, the characteristic of electrode material is needed to low work function, low sputtering ratio and superior manufacturing property. We developed new CCFL with Nb/Ni Clad electrode superior to conventional CCFL. Because Nb/Ni Clad electrode with Ni material and Nb material, the electrical characteristic is superior to other electrode materials. The electrode of Nb/Ni Clad is composed that Ni of outside material has superior manufacturing property and Nb of inside material has low work function. Nb/Ni Clad of new electrode material is made by process of Rolling mill at high pressure and heat treatment. We compared electrical characteristic of Nb/Ni clad electrode with conventional Mo electrode by measurement. Mo electrode and Nb/Ni Clad electrode of cup type with diameter 1.1 mm and length 3.0mm are used to this experiment. Material content of Mo electrode is Mo 100%. But, Nb/Ni Clad electrode is composed by content of Nb 40% and Ni 60%. The result of comparison measurement between new CCFL with Nb/Ni Clad electrode and conventional CCFL was appeared that CCFL with Nb/Ni Clad electrode had superior characteristic than conventional CCFL. As a result of experiment, we completed Note PC with low power consumption and long life time by application of new CCFL with Nb/Ni Clad electrode.

• Journal of Auto-vehicle Safety Association
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• v.14 no.2
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• pp.90-95
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• 2022

Composite material is widely used in the automotive industries because it has excellent mechanical properties and is possible to reduce weight due to the low density. However, there is a new obstacle to meet environment regulation like Cu less or Cu free regulation for the friction material. Although it is strongly demanded, there are few research results about that unfortunately. Unless this problem is not solved properly, it is impossible to apply composite brake system to vehicle. In this paper, a new eco-friendly friction material for composite brake system is represented to respond these regulations. To do this, friction characteristics between existing low steel friction material and new eco-friendly friction material are verified to secure performances for brake system such as effect characteristic, fade characteristic and wear characteristic. And composite brake gets the equivalent or better performance compared to a low steel friction material. Finally, this result contributes to the study of major principles for the development of eco-friendly friction material in the future.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.526-529
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• 2002

Various fluoride films on a glass substrate were prepared and characterized in order to determine the best seed layer for a microcrystalline silicon (${\mu}c$-Si) film growth. Among the various group-IIA-fluoride systems, the $CaF_2$films on glass substrates illustrated (220) preferential orientation and a lattice mismatch of less than 0.7% with Si. $CaF_2$ films exhibited a dielectric constant between $4.1{\sim}5.2$ and an interface trap density ($D_{it}$ as low as $1.8{\times}10^{11}\;cm^{-2}eV^1$. Using the $CaF_2$/glass structure, we were able to achieve an improved ${\mu}c$-Si film at a process temperature of 300 $^{\circ}C$. We have achieved the ${\mu}c$-Si films with a crystalline volume fraction of 65%, a grain size of 700 ${\AA}$, and an activation energy of 0.49 eV.