• 한국소음진동공학회논문집
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• 제23권1호
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• pp.84-91
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• 2013

Ultrasonic flip-chip bonding needs a precise bonding tool which delivers ultrasonic energy into chip bumps effectively to use the selected resonance mode and frequency of the horn structure. The bonding tool is excited at the resonance frequency and the input and output ports should locate at the anti-nodal points of the resonance mode. In this study, we propose new design method with topology optimization for ultrasonic bonding tools. The SIMP(solid isotropic material with penalization) method is used to formulate topology optimization and OC(optimal criteria) algorithm is adopted for the update scheme. MAC(modal assurance criterion) tracking is used for the target frequency and mode. We fabricate two prototypes of ultrasonic tools which are based on 3D optimization models after reviewing 2D and 3D topology optimization results. The prototypes are satisfied with the ultrasonic frequency and vibration amplitude as the ultrasonic bonding tools.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 추계학술대회 논문집
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• pp.467-468
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• 2012

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.1134-1135
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• 2006

A revolutionary "Active Braze Coated Diamond" (ABCD) has been developed for bonding diamond grits firmly in the metal matrix. The molten braze is wetted and reacted with diamond to form strong chemical bond at the interface so that the diamond does not become knocked out of tools. The ABC is a nickel alloy that can form metallurgical diffusion bondswith the metal matrix. In essence, ABCD turns diamond into a metal grain so that the diamond tools can be made by conventional powder metallurgical process without being concerned about the poor bonding between matrix metal powder and the diamond as before.

• 부모자녀건강학회지
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• 제6권2호
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• pp.93-102
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• 2003

The study was designed to examine the effect of perceived past parent-child bonding on present parent-child attachment, self-concept. The data collection period was October 6-18, 2003. The subject was college students in university located in Nonsan, Taejon city and 197 surveys were used in the analysis. As for the tools used in this study to assess the perceived past parent - child bonding scale by Parent Bonding Instrument - Korean Version, and present parent-child attachment were measured with the The Inventory of Parent and Peer Attachment, and self-concept were measured with Jung, Won Sik's self-concept inventory. For the data processing, the analyses of variance, multiple regression, correlation were carried out. The result of this study is summarized as follows. 1. The examination of the effect of perceived past parent-child bonding on present parent-child attachment showed that significant differences are made by communication, trust, alienation in care, overprotection perceived past parent-child bonding. 2. As for the correlation between perceived past parent-child bonding and child self-concept, a significant correlation is revealed between care, overprotection perceived past parent-child bonding and child self-concept.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2002년도 Proceedings of the International Welding/Joining Conference-Korea
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• pp.402-407
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• 2002

Laminate tooling process is a fast and simple method to make metal tools directly for various molding processes such as injection molding in rapid prototyping field. Metal sheets are usually cut, stacked, aligned and joined with brazing or soldering. Through the joining process, all of the metal sheet layers should be rigidly joined. When joining process parameters are not appropriate, there would be defects in the layers. Among various types of defects, non-bonded gaps of the tool surface are of great importance, because they directly affect the surface quality and dimensional accuracy of the final products. If a laminate tool with defects has to be abandoned, it could lead to great loss of time and cost. Therefore a repair method for non-bonded gaps of the surface is essential and has important meaning for rapid prototyping. In this study, a rapid laminate tooling system composed of a CO2 laser, a furnace, and a milling machine was developed. Metal sheets were joined by furnace brazing, dip soldering and adhesive bonding. Joined laminate tools were machined by a high-speed milling machine to improve surface quality. Also, repair brazing and soldering methods of the laminates using the $CO_2$ laser system have been investigated. ill laser repair process, the beam duration, beam power and beam profile were of great importance, and their effects were simulated by [mite element methods. The simulation results were compared with the experimental ones, and optimal parameters for laser repair process were investigated.

• 한국과학교육학회지
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• 제43권2호
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• pp.181-190
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• 2023

이 연구에서는 증강현실을 활용한 소집단 학습에서 도구 사용 환경에 따른 담화를 참여 유형, 담화의 유형, 지식 형성 과정 측면에서 비교하였다. 고등학교 1학년 학생 24명을 6개 모둠으로 나눈 후, 마커 1개와 스마트 기기 1개를 공동으로 사용하는 도구 공유 환경과 마커와 스마트 기기를 개별로 사용하는 개별 도구 환경에 각각 배치하였다. 학생들은 모둠별로 물질의 규칙성과 결합 단원에서 다루는 개념을 주제로 증강현실 애플리케이션을 활용한 소집단 학습에 참여하였다. 모든 수업 과정은 모둠별로 녹음 및 녹화하였으며, 자발적으로 동의한 학생 6명을 대상으로 반구조화된 면담을 실시하였다. 연구결과, 도구 공유 환경은 일인 주도형의 비율이 높았으나, 개별 도구 환경은 부분 참여형 및 다수 참여형의 비율이 높았다. 개별 도구 환경은 도구 공유 환경보다 지식 공유와 지식 구성 담화의 비율이 유사하였고, 세부 담화 유형도 다양하였다. 도구 공유 환경에서는 일부 학생에 대해서만 의미 있는 지식 형성 과정이 나타났다. 반면 개별 도구 환경에서는 모둠원 대부분이 목표 개념에 대해 올바른 지식을 구성하며 의미 있는 지식 형성 과정이 이루어졌으며, 일부 모둠원에게 나타난 오개념은 소집단 토의를 통해 올바른 과학 개념으로 수정되었다.

• 한국기계가공학회지
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• 제14권2호
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• pp.25-30
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• 2015

This study involved the fabrication of precision machine tools using a polycrystalline diamond tip [sintered PCD and cemented carbide (WC-Co) tip] and WC-Co shanks via diffusion bonding with a paste-type nickel alloy filler metal. Diffusion bonding is a process whereby two materials are pressed together at high temperature and high pressure for a sufficient period of time to allow significant atomic diffusion to occur. For smooth progress, a filler metal of nickel alloy was used at the interface. Optical microscopy images were used to observe the copula of the bonded layer. It was confirmed that cracks occurred near the junction in all cases. The tensile strength of the bond was measured using a universal testing machine (UTM) with WC-Co proportional test specimens.

• 농촌의학ㆍ지역보건
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• 제37권3호
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• pp.111-130
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• 2012

Objective: The purpose of this study was to identify and compare social capital measurement tools for the convenient use in public health studies. Method and result: This study examined and compared social capital tools developed individually by the World Bank, the OECD, the United States, United Kingdom, Canada, Australia, Ireland, and Korea. A comprehensive framework was constructed with six conceptual dimensions and sixteen indices. The six dimensions included Membership, Network, Trust, Information and communication, Social and civic participation, and Social cohesion and exclusion, which connoted the structural, cognitive, bonding, bridging, operative, and output elements. The indices of each tool were respectively matched to the indices of the comprehensive framework. The comprehensive tools were Integrated Questionnaire for the Measurement of Social Capital (SC-IQ) of the World Bank with 27 questions and the European Social Survey (ESS) of the OECD with 80 questions. Conclusion: The SC-IQ should be utilized in public health studies due to its simplicity yet comprehensiveness as a social capital tool. The ESS should also be considered as a comprehensive tool.

• 한국분말재료학회지
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• 제5권4호
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• pp.303-311
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• 1998

Hard materials such as hardmetal, coated hardmetal, cermet, ceramics and diamond or c-BN sintered compact are a kind of grain-dispersed alloy with high volume of hard particles. These are used for cutting tools, wear-resistant tools, rock bits, high pressure apparatus, etc. The annual production in Japan is about 1.7 billion dollars (200 billion yen). This is greatly owed to the development in science and technology which has been accomplished by applying new concepts such as fine or uniform grain microstructure, orientation of crystal grains, functionally graded material, artificial lattice and coherent bonding in recent years. In this review, the development in recent years in Japan is briefly summarized.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2002년도 춘계학술발표대회 논문집
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• pp.163-166
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• 2002

For the development of an all composite unmanned aerial vehicle (UAV), manufacturing consideration in design phase, works for composite parts fabrication, subassembly and final assembly are summarized. In design phase, to maximize the advantage of composite material, manufacturing processes such as cocuring, cobonding and secondary bonding are introduced. For the curing of designed parts, composite tools are designed and manufactured. Assembly jigs are designed to satisfy dimensional tolerance of the structure. Inspection criteria are established and applied to the manufacturing. Technical data about inspection items and methods are summarized as manufacturing specifications for the mass production of the UAV structure.