• Journal of Powder Materials
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• v.6 no.1
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• pp.36-41
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• 1999

The present work has attempted to investigate the dependence of Cu infiltration kinetics on in-situ structure modification of W powder skeleton in W-Cu system. In-situ structure modification of W skeleton by addition of 0.3wt%Ni-P eutectic alloy was designed to proceed during heat-up of the W compact for Cu infiltration process. It was found that the Ni-P added W skeleton underwent remarkable stucture change only during heating-up. its structure was composed of large necks of W particles above 0.5 in the ratio of neck to particle size and smooth pore channels. The infiltration experiment showed that the infiltration kinetics for the W-Ni-P followed well the linear relationship of h vs. $t^{1/2}$ the rate constant K of which was in good agreement with the theoretical value. On the other hand, in case of the pure W skeleton a lower K value by 20% than the theoretical one was obatined. Such discrepancy is discussed in terms of skeleton structure induced infiltration mechanics.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.948-949
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• 2006

An infiltration technique using W-Cu composite powder has been developed to enhance microstructural uniformity of W-Cu pseudo-alloy. W-Cu composite powder, manufactured by reduction from $WO_3$ and CuO powder mixtures, were blended with W powder and then cold iso-statically pressed into a cylindrical bar under 150 MPa. The pressed samples were pre-sintered at $1300^{\circ}C$ for 1 hour under hydrogen to make a skeleton structure. This skeleton structure was more homogeneous than that formed by using W and Cu powder mixtures. The skeleton structures were infiltrated with Cu under hydrogen atmosphere. The infiltrated W-Cu pseudo-alloy showed homogeneous microstructure without Cu rich region

• Nuclear Engineering and Technology
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• v.54 no.12
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• pp.4491-4498
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• 2022

The thermal stress between W plasma-facing material (PFM) and Cu heat sink in fusion reactors can be significantly reduced by using a W-Cu functionally graded material (W-Cu FGM) interlayer. However, there is still considerable stress at the joining interface between W and W-Cu FGM in the W/W-Cu FGM/Cu portions. In this work, we fabricate W skeletons with continuous gradients in porosity by a modified sedimentation method. Sintering densification behavior and pore characteristics of the sedimented W skeletons at different sintering temperatures were investigated. After Cu infiltration, the final W-Cu FGM was obtained. The results indicate that the pore size and porosity in the W skeleton decrease gradually with the increase of sintering temperature, but the increase of skeleton sintering temperature does not reduce the gradient range of composition distribution of the final prepared W-Cu FGM. And W-Cu FGM with composition distribution from pure W to W-20.5wt.% Cu layer across the section was successfully obtained. The thickness of the pure W layer is about one-fifth of the whole sample thickness. In addition, the prepared W-Cu FGM has a relative density of 94.5 % and thermal conductivity of 185 W/(m·K). The W-Cu FGM prepared in this work may provide a good solution to alleviate the thermal stress between W PFM and Cu heat sink in the fusion reactors.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1988.10a
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• pp.64-66
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• 1988

The present investigation has been performed on the manufacturing process of Ni-P doped W-Cu electric contacts by infiltration techniques. The addition of small amount of Ni-P alloy aimed at forming a rigid and homogeneous skeleton structure of W-powders which favours subsequent infiltration process of Cu-melts. The experimental results revealed that the small addition of Ni-P alloy appreciably enhances the sintering process of W at low temperatures (even at 1000$^{\circ}C$), simultaneously causing a considerable change of skeleton Morphology and its related best infiltration behaviour of Cu-melts.

• Proceedings of the KIEE Conference
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• 1997.07e
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• pp.1804-1806
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• 1997

Route conditions, applied voltage and the condition of stringing conductors should be considered in determining standard types and skeleton diagrams of towers. In skeleton diagrams the necessary number of insulators and the air clearance have been decided by the results of studies on insulation coordination. Galloping, sleet-jumping, sag characteristics and the possibility of closeness of conductors should be considered according to the condition of stringing conductor and the span. After reviewing those factors, it is necessary to determine the minimum vertical and horizontal distance for the safety of transmission lines under any circumstances. Also it should be economical.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.910-913
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• 2001

Rapid Prototyping(RP) techniques have unique characteristics according to their working principle: the stair-stepped surface of a part due to layer-by-layer stacking, low building speed, and additional post-processing to improve surface roughness. A new RP process, Variable Lamination Manufacturing by using expandable polystyrene foam(VLM-S), has been developed to overcome the unfavorable characteristics. The objective of this study is to investigate the thermal characteristics and skeleton size effects as the hotwire cuts EPS foam sheet in order to improve dimensional accuracy of the parts, which is produced by VLM-S. Empirical and analytical approaches are performed to find the relationship between cutting speed and heat input, and the relationship between maximum available cutting speed and heat input. In addition, empirical approaches are carried out to find the relationship between cutting error and skeleton size, and cutting deviation and skeleton size. Based on these results, the optimal hotwire cutting condition and available minimum skeleton size are derived. The outcomes of this study are reflecting in the enhancement of VLM-S input data generation S/W.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.7
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• pp.138-146
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• 1996

In this paper, w epropose a new mehtod to represent the shape and to recognize the object. The shape description and the matching is implemented by using the distance transform on the morphological skeleton. The employed distance transform is the chamfer (3,4) distance transform, because the chamfer distance transform (CDT) has an approximate value to the euclidean distance. The 2-D object can be represented by means of the distribution of the distance transform on the morphological skeleton, the number of skeletons, the sum of the CDT, and the other features are employed as the mtching parameters. The matching method has the invariant features (rotation, translation, and scaling), and then the method is used effectively for recognizing the differently-posed objects and/or marks of the different shape and size.

• Proceedings of the KIEE Conference
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• 1998.07c
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• pp.1185-1187
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• 1998

The object of this study shows a program for supervisory control of the electric power distribution, approach to the more easy manipulations and hangulization that could be easily familiar to the domestic operators whereas the program, up to now, displayed only in English. This program is consist of a skeleton-diagram designer and a state-displayer of the electric power distribution To make skeleton-diagram data available in state-displayer, the designer must be performed with the proposed format in the program manual. States display executes downloading S/Ws-state-data externally and display the S/W informations at that times, and also power distribution simulation of voluntary S/W manipulations performed by the internal operators is possible.

• International Journal of Contents
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• v.12 no.2
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• pp.24-30
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• 2016

Ontology is known to be one of the most important technologies in achieving semantic web. It is critical as it represents the knowledge in a machine readable state. World Wide Web Consortium (W3C) has been contributing to the development of ontology for the last several years. However, the recommendation of W3C left out HTML despite the massive amount of information it contains. Also, it is difficult and time consuming to keep up with all the technologies especially in the case of constructing ontology. Thus, we propose a module and methods that reuse HTML documents, extract necessary information from HTML tags and mapping it to OWL 2. We will be combining two kinds of approaches which will be the structural refinement for making an ontology skeleton and linguistic approach for adding detailed information onto the skeleton.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.1365-1366
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• 2010