• 한국분말재료학회지
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• 제28권4호
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• pp.287-292
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• 2021

In this study, the layered structures of immiscible Fe and Cu metals were employed to investigate the interface evolution through solid-state mixing. The pure Fe and Cu powders were cold-consolidated by high-pressure torsion (HPT) to fabricate a layered Cu-Fe-Cu structure. The microstructural evolutions and flow of immiscible Fe and Cu metals were investigated following different iterations of HPT processing. The results indicate that the HPT-processed sample following four iterations showed a sharp chemical boundary between the Fe and Cu layers. In addition, the Cu powders exhibited perfect consolidation through HPT processing. However, the Fe layer contained many microcracks. After 20 iterations of HPT, the shear strain generated by HPT produced interface instability, which caused the initial layered structure to disappear.

• Nuclear Engineering and Technology
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• 제53권5호
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• pp.1593-1601
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• 2021

Oxide dispersion strengthening (ODS) tungsten alloys are highly desirable in irradiation applications. However, how to improve the properties of ODS-tungsten alloys efficiently has been worth studying for a long time. Here we report a nanostructuring approach that achieves W-La₂O₃ alloy with a high level of flexural strength and Vickers hardness at room temperature, which have the maximum value of 581 MPa and 703 Hv, respectively. This method named solution combustion synthesis (SCS) can generate 30 nm coating structures W-La₂O₃ composite powders by using Keggin-type structural polyoxometalates as raw materials in a fast and low-cost process. The composite powder can be fabricated to W-La₂O₃ alloy with an optimal microstructure of submicrometric W grains coexisting with nanometric oxide particles in the grain interior, and a stability interface structure of grain boundaries (GBs) by forming transition zones. The method can be used to prepare new ODS alloys with excellent properties in the future.

• 한국멀티미디어학회논문지
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• 제18권5호
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• pp.663-670
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• 2015

In this study, I have researched the theories about Gibson's real affordance and Norman's perceived affordance which are central fact of affordance, And I have examined the context of affordance in smart-phone interface which was consist of affordance and signifier with viewpoint of amalgamation of Gibson & Norman. The results of this study are as follows; The first, Gibson's real affordance is a physical space in ubiquitous environment that interact through the behavioral space is composed with physical space and electronic space. Norman's perceived affordance is mediated to electronic space and signifier makes a behaviroal space which provide the clue of interaction. The second, signifier can be categorized into visceral, behavioral and reflective signifier based on three brain actions which are visceral, behavior, and reflection. Through the categorization, we can grasp that behavioral and reflective signifies generate visceral signifier. The third, the context of affordance in smart-phone has the structure of circulation. The structure of circulation is as follows: Real affordance makes the perceived affordance, the perceive affordance makes the signifiers and the signifiers make new real affordance. This study could provide the theoretical basis for using signifier in smart-phone interface design.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1998년도 춘계학술대회논문집; 용평리조트 타워콘도, 21-22 May 1998
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• pp.444-449
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• 1998

A modal transducer in two-dimensional structure can be implemented by varying the distributed transducer's gain spatially. In this paper, a method based on finite element method is developed for optimizing spatial gain distribution of PVDF transducer to create the modal transducer for specific modes. Using this concept, one can design the modal transducer in two-dimensional structure having arbitrary geometry and boundary conditions. As a practical means for implementing this continuous gain distribution without repoling die PVDF film, the gain distribution is approximated by optimizing gain-weights of interface circuit. The whole spatial area of the PVDF film is divided into several electrode segments and the signals from each segment are properly weighted and summed by interface circuit. This corresponds to the approximation of a continuous function using discrete values. The electrode partition is optimized using the genetic algorithm. Gain-weights are optimized using the simplex search method. A modal sensor for first to fourth modes of aluminum plate is designed using PVDF film with gain-weighted interface circuit. Various lamination angles of PVDF film are taken into consideration to utilize the anisotropy of the PVDF film. Performance of the optimized' PVDF sensor is demonstrated by numerical simulations..

• 한국결정성장학회지
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• 제5권2호
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• pp.100-108
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• 1995

SOI구조를 얻기 위한 방법의 한가지인 ZMR공정에 있어서 열전달은 계면의 위치와 모양을 결정하는 중요한 역할을 한다. 본 연구에서는 SOI구조를 얻기 위한 ZMR공정중의 열전달 공정을 모사할 수 있는 의사정상상태 2차원 ZMR모델을 수립하였다. 본 모델은 복사, 전도 그리고 대류 열전달을 포함하며, 고/액 계면의 위치를 결정한다. 모델로부터 구한 수치해는 실리콘 기판의 용융부에서의 유동장, 전체 SOR구조에서의 온도장 그리고 실리콘 박막과 기판에서의 고/액 계면의 위치를 포함한다. 여러 공정 변수들의 변화에 따른 온도장과 계면의 형상과 폭의 변화를 알아보았다.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2005년도 춘계 종합학술대회 논문집
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• pp.443-447
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• 2005

텔레매틱스를 위한 임베디드 이동체 자동화시스템(EMAST : Embedded Mobile Automatic System for Telematics)인 EMAST는, CAN(Controller Area Network)과 ARM Processor를 이용한 임베디드 이동체 자동화 시스템을 단일 칩(System-on-Chip)으로 구현된다. EMAST가 범용적으로 사용되기 위해서는 다음 두 조건을 만족해야만 한다. 첫째, 이동체 내부 인터페이스는 Differential Transceiver와 Optical Transceiver, Wireless Transceiver를 지원하도록 설계되어야하며, 둘째, EMAST와 텔레매틱스 망을 사용하는 단말기들 간의 인터페이스를 지원해야만 한다. 본 논문에서는 텔레매틱스를 위한 임베디드 이동체 자동화 시스템 구조 및 EMAST와 이동체각 Unit들과의 효율적인 인터페이스 구조를 제안하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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• pp.459-462
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• 2001

Interface effects on properties of NTC thermistors having Mn-Co-O spinel crytal structure system are analyzed by a mixing rule in case of mixed types and layered types between CuO and $Al_{2}O_{3}$ added compounds. With adding CuO and $Al_{2}O_{3}$, The compounds form completely solid solution and their resistance and B constant are changed due to the variation of conduction electrons by their ionic substitutions. The properties of mixed NTC thermistors are depended on the logarithmic mixing rule by a dispersed phase and they show slightly lower values due to the lattice mixing affect in compared with calculated values. The resistance of layered NTC thennistors is depended upon the series mixing rule containing the value of an interface layer and effected by the variation of its thickness, and it is changed rapidly to the logarithmic mixing rule by the connection between two layers with increasing the interface layer.

• 대한전자공학회논문지
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• 제12권4호
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• pp.35-40
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• 1975

ZnTe-lnSb Heterojunction을 계면합금법으로 제작했다. Insb의 In이 ZnTe결정에 확산되어 계면에 고저항 ZnTe충을 성장시켜 P-i-n구조를 갖고 있으며 전류수송기구는 p형 ZnTe 가전자대로부터 고저항 ZnTe충에 주입된 Hole의 SCLC기구에 의존된다. 순방향과 역방향 전압을 인가할때 실온에서 오런지색 전 장발장이 관측되었다. The Zn7e-lnSb heterojunctions was prepared by interface alloying technique. The structure of this beterojunction had p-i-n which semi-insulating ZnTe laver at interface of this heterojunction was formed by diffusing In of InSb into ZnTe crystal. The current transport mechanism of this heterojunction was Spacecharge-Limited-Current(SCLC) mechanism by hole at semi-insulating ZnTe layer. The hole wart injected from valence band of p- type SnTe crystal. Orange color electroluminescence was observed at this heterojunction when forward and reversed bias voltage applied.

• 열처리공학회지
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• 제31권2호
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• pp.49-55
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• 2018

A T-shape structure was manufactured by the superplastic forming and diffusion bonding process using two Ti-3Al-2.5V alloy tubes. A Ti-3Al-2.5V tube was prepared for the hydroforming in the superplastic condition until it reaches a surface area such as a roof welded in the hole of another Ti-3Al-2.5V tube. Afterward, the superplastic forming process and the diffusion bonding process were carried out simultaneously until the appropriate bonding along the interface area of two Ti-3Al-2.5V tubes was obtained. The bonding qualities were different at each location of the entire interface according to the applied process conditions such as strain, pressure, temperature, holding time, geometries, etc. The microstructures of bonding interface have been observed to understand the characteristics of the applied processes in this study.

• 대한인간공학회지
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• 제23권4호
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• pp.9-21
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• 2004

As menu structure of household appliance is complicated, user's cognitive workload frequently occurs errors. In existing studies, errors didn't present that interpretation for cognitive factors and alternatives, but are only considered as statistical frequency. Therefore, error classification and analysis in tasks is inevitable in usability evaluation. This study classified human error throughout information process model and navigation behavior. Human error is defined as incorrect decision and behavior reducing performance. And navigation is defined as unrelated behavior with target item searching. We searched and analyzed human errors and its causes as a case study, using mobile phone which could control appliances in near future. In this study, semantic problems in menu structure were elicited by SAT. Scenarios were constructed by those. Error analysis tests were performed twice to search and analyze errors. In 1st prototype test, we searched errors occurred in process of each scenario. Menu structure was revised to be based on results of error analysis. Henceforth, 2nd Prototype test was performed to compare with 1st. Error analysis method could detect not only mistakes, problems occurred by semantic structure, but also slips by physical structure. These results can be applied to analyze cognitive causes of human errors and to solve their problems in menu structure of electronic products.