SOFC 연결재용 Al이 도핑된 (La_0.8Ca_0.2)(Cr_0.9Co_0.1)O₃(LCCC)계 세라믹스의 합성 및 치밀화 특성

이호영,강보경,이호창,허영우,김정주,김재육,이준형,Lee, Ho-Young,Kang, Bo-Kyung,Lee, Ho-Chang,Heo, Young-Woo,Kim, Jeong-Joo,Kim, Jae-Yuk,Lee, Joon-Hyung 한국전기전자재료학회 2012 전기전자재료학회논문지 Vol.25 No.5

In the $(La_{0.8}Ca_{0.2})(Cr_{0.9}Co_{0.1})O_3$ (LCCC), which has been using as interconnector materials in SOFC, Al ions were substituted for Co because ionic radius of Al is similar to that of Co. Because of the almost identical ionic radius of Al and Co, the substitution was not thought to be affect the tolerance factor of LCCC, and the densification behavior, high temperature electrical conductivity and thermal expansion coefficient were examined as a function of Al concentration. In the cases of the x= 0 and x= 0.02 in $(La_{0.8}Ca_{0.2})(Cr_{0.9}Co_{0.1-x}Al_x)O_3$ (x= 0~0.1), the samples showed the relative densities above ${\geq}95%$ when those were sintered at ${\geq}1,350^{\circ}C$. In the case of the $x{\geq}0.06$ the sintered density deteriorated greatly at lower sintering temperatures. High temperature electrical conductivity of the samples decreased as the content of Al increased. Since the valence state of Al ion is unchangeable, while Cr or Co ions contribute to the electrical conduction by changing those valence states, Al substitution resulted in the decreased electrical conductivity. Al doping of LCCC was an effective way of decreasing the thermal expansion coefficient (TEC).

The Pronunciation of English Consonant Clusters by Koreans

이호영,Lee Ho-Young The Korean Society Of Phonetic Sciences And Speech 2000 말소리 Vol.40 No.-

한국어와 영어는 서로 다른 음소 배열 제약과 음운 규칙을 가지고 있기 때문에 영어 학습자들은 특정 영어 자음군을 정확하게 발음하는 데 어려움을 겪게 된다 따라서 이 논문은 영어 학습자들이 어떤 영어 자음군을 배우기 어려워 하고 왜 이러한 어려움이 생겨나는지 한국어와 영어의 음소 배열 제약과 음운 규칙을 비교해서 밝히는 것을 목적으로 한다.

인장하중하에서의 고분자/거친금속 계면의 파손에 대한 비교연구 I: 실험결과

이호영,김성룡,Lee Ho-Young,Kim Sung-Ryong 한국재료학회 2005 한국재료학회지 Vol.15 No.1

Copper-based leadframe sheets were immersed in two kinds of hot alkaline solutions to form brown-oxide or black-oxide layer on the surface. The oxide-coated leadframe sheets were molded with epoxy molding compound (EMC). After post mold curing, the oxide-coated EMC-leadframe joints were machined to form sandwiched double-cantilever beam (SDCB) specimens. The SDCB specimens were used to measure the fracture toughness of the EMC/leadframe interfaces under quasi-Mode I loading conditions. Fracture surfaces were analyzed by various equipment to investigate failure path. The present paper deals with the failure path, and the cause of the failure path formation with an adhesion model will be treated in the succeeding paper.

한국어의 변이음 규칙과 변이음의 결정 요인들

이호영,Lee Ho-Young 대한음성학회 1992 말소리 Vol.21 No.-

This paper aims to discuss determining factors of Korean allophones and to formulate and classify Korean allophonic rules systematically. The relationship between allophones and coarticulation, the most. influential factor of allophonic variation, is thoroughly investigated. Other factors -- speech tempo and style, dialect, and social factors such as age, set, class etc. -- are also briefly discussed. Allophonic rules are classified into two groups -- 3) those relevant to coarticulation and 2) those irrelevant to coarticulation. Rules of the first group are further classified into four subgroups according to the directionality of the coarticulation. Each allophonic nile formulation is explained and discussed in detai1. The allophonic rules formulated and classified in this paper are 1) Devoicing of Voiced Consonants, 2) Devoicing of Vowels, 3) Nasal Approach and Lateral Approach, 4) Uvularization, 5) Palatalization, 6) Voicing of Voiceless Lax Consonants, 7) Frication, 8) Labialization, 9) Nasalization, 10) Release Withholding and Release Masking, 11) Glottalization, 12) Flap Rule, 13) Vowel Weakening, and 14) Allophones of /ㅚ, ㅟ, ㅢ/ (which are realized as diphthongs or as monophthongs depending on phonetic contexts).

산화처리된 구리계 리드프레임과 EMC 사이의 접착력 측정

이호영,유진,Lee, Ho-Young,Yu, Jin 한국재료학회 1999 한국재료학회지 Vol.9 No.10

Due to the inherently poor adhesion strength of Cu-based leadframe/EMC(Epoxy Molding Compound) interface, popcorn-cracking phenomena of thin plastic packages frequently occur during the solder reflow process. In this study, in order to enhance the adhesion strength of Cu-based leadframe/EMC interface, brown-oxide layer was formed on the leadframe surface by immersing of leadframe sheets in hot alkaline solution, and the adhesion strength of leadframe/EMC interface was measured by using SDCB(Sandwiched Double Cantilever Beam) and SBN(Sandwiched Brazil-Nut) specimens. Results showed that brown oxide treatment of leadframe introduced fine acicular CuO crystals on the leadframe surface and improved the adhesion strength of leadframe/EMC interface. Enhancement of adhesion strength was directly related to the thickening kinetics of oxide layer. This might be due to the mechanical interlocking of fine acicular CuO crystals into EMC. 본래 약한 구리계 리드프레임/EMC(Epoxy Molding Compound) 계면의 접착력은 솔더 리플로우 (solder reflow) 공정 중에 종종 박형 플라스틱 패키지의 팝콘 균열 현상(popcorn-cracking phenomena)을 일으킨다. 본 연구에서는 리드프레임/EMC 계면의 접착력을 향상시키기 위하여 리드프레임을 알칼리 용액에 담궈 표면에 brown oxide를 형성시켰으며, EMC로 몰딩(molding)하여 SDCB(Sandwiched Double Cantilever Beam) 시편 및 SBN(Sandwiched Brazil-Nut) 시편을 준비하여 접착력을 측정하였다. 리드프레임의 brown oxide 처리는 미세한 바늘모양의 CuO 결정들을 리드프레임 표면에서 형성시켰으며, 리드프레임/EMC 계면의 접착력을 향상시켰다. 접착력의 향상은 산화층의 평균두께와 직접적인 관련이 있었다. 이는 미세한 바늘모양의 CuO 결정들이 EMC와 기계적인 고착(mechanical interlocking)을 하기 때문으로 생각된다.

기술과 자유로운 상상의 연결 패러다임

이호영,Lee, Ho Young 연세대학교 의과대학 2011 의학교육논단 Vol.13 No.2

The status of medical doctors is relatively high in society. However, in spite of this acknowledged status, physicians are not aware of the extent to which they have the ability to care for patients or how much effort they should make to meet people's expectations. Therefore, we should examine what society asks of doctors and how doctors need to be educated to meet the expectations of society. In this article, the author asserts that physicians need four skills. First, doctors should know how to speak and communicate. In the work of a doctor, language is the most important for tasks such as understanding texts, communication with patients, analyzing data, and starting new projects. Second, doctors should have intuition. In a doctor's medical judgment, intuition is very important and it can initiate from an educated guess. In other words, good intuition can be developed based on a good educated guess, which in turn can derive from one's explored knowledge, communication with one's inner dialogues, and good interpretation skill. Third, doctors should have creativity. Doctors should produce an image about patients from intuition, and those intuitions are based on creativity. Usually, students in medical school have creative ability; therefore, the instructor should facilitate their learning to connect this creativity to free imagination ability and medical skills. Fourth, doctors should be humane. Patients want to communicate with doctors about their disease and further about their lives. The reason why a humane doctor is important is that this humane approach itself could cure patients and reduce their pain. When a doctor's humane attitude is realized in the hospital, the patients and doctors could be pleased sincerely.

Foraminifera from shell deposits of the Jindo Island

이호영,Lee Ho-Young The Korean Society Of Petroleum Geology 1993 한국석유지질학회지 Vol.1 No.1

진도에 분포되는 패각층의 유공충 군집은 온난환경에서 퇴적되었음을 지시한다. 총 12개의 표품에서 10속 11종의 저서성 유공충이 산출되었다. 이중에서 Cavarotalia annectens가 주요종으로 57에서 90퍼센트를 차지한다. 본역의 패각층은 유공충 군집으로 보아 흘로세 퇴적물이다. Foraminiferal assemblages from shell beds of Jindo Island indicate shallow water accumulation under warm to temperate condition near the mouth of a small estuary. 11 species of benthonic Foraminifera belonging to 10 genus have been extracted from 12 samples. Cavarotalia annectens dominates, accounting for 57 to 90 percent of the total fauna. The foraminiferal assemblages of the shell beds indicates Post-glacial sedimentation.

혼합 하중하에서의 고분자/거친금속 계면의 파손경로

이호영,김성룡,Lee Ho-Young,Kim Sung-Ryong 한국재료학회 2004 한국재료학회지 Vol.14 No.5

Copper-based leadframe sheets were oxidized in two kinds of hot alkaline solutions to form brown-oxide or black-oxide layer on the surface. The oxide coated leadframe sheets were molded with epoxy molding compound (EMC). After post mold curing, the oxide-coated EMC-leadframe joints were machined to form sandwiched Brazil-nut (SBN) specimens. The SBN specimens were used to measure the fracture toughness of the EMC/leadframe interfaces under mixed-mode (mode I + mode II) loading conditions. Fracture surfaces were analyzed by various equipment to investigate failure path. The results revealed that the failure paths were strongly dependent on the oxide type. In case of brown oxide, hackle-type failure was observed and failure path lay near the EMC/CuO interface with a little inclining to CuO at all case. On the other hand, in case of black oxide, quite different failure path was observed with respect to the distance from the tip of pre-crack and phase angle. Different failures occurred with oxide type is presumed to be due to the difference in microstructure of the oxides.

수종의 치근형 골내매식체와 조직간의 반응에 관한 조직학적 연구

이호영,김영수,Lee, Ho-Young,Kim, Yung-Soo 대한치과보철학회 1990 대한치과보철학회지 Vol.28 No.1

The success or failure of endosseous dental implants is related to the cellular activity at the implant surface. Success seems to be associated with the enclosure of the implant in a non-inflammed connective tissue or the formation of a direct bone implant interface. The purpose of this study was to examine the tissue reactions to the various implants at the submergible state in dog mandible. The $Br\"{a}nemark$, Core-Vent, Intergral, Bone spiral were selected for evaluation and also the Kimplant, Nephrite were used for the experimental study. After 4 months the animals were sacrificed. The interface zone between bone and implant was investigated using x-rays, light microscope, scanning electron microscope, transmission electron microscope. The following results were obtained from this study. 1. $Br\"{a}nemark$, Core-Vent, Kimplant, Integral showed no mobility and bone growth over the healing screws of the implants. Histologically most of the implant surface were covered by remodelled lamellar bone, and partly by a cellular layer or the thin fibrous tissue layer. 2. The Bone spiral showed no mobility and partially radiolucent line around the implant. The upper part of the implant was surrounded by a thin fibrous connective tissue and the middle, apical part of it were contacted with bone directly. 3. The Nephrite implant showed severe mobility and a radiolucent line around the implant. Histologically it showed mild inflammation and was surrounded by a fibrous connective tissue. 4. Scanning electron microscope showed that there was no amorphous ground substance in the Nephrite implant but the formation of ground substance over the collagen filaments in other implants. 5. Transmission electron microscope showed that collagen filaments were approached irregularly to the surface of all implants and in the $Br\"{a}nemark$, Core-Vent, Kimplant, Integral there was amorphous layer between the implant and the collagen filaments. It seemed to be ground substances.

국어 핵억양의 음향음성학적 연구

이호영,Lee Ho-Young 대한음성학회 1999 말소리 Vol.38 No.-

Korean intonation has been investigated mainly from the point of view of impressionistic phonetics and phonology. The purpose of this paper is to investigate Korean intonation especially nuclear tones, from the point of view of experimental phonetics. Since what we hear is not always the always as what we see in fundamental frequency contours, acoustic characteristics of Korean nuclear times are first discussed Based m quantitative data similar nuclear times are compared and the relationship between the nuclear ton and sentence type is investigated The relationship between the nuclear tone and the speaker's attitude is also discussed.