Cu-Fe계 합금의 강도 및 전기전도도에 미치는 Cr 원소첨가의 영향

김대현,이광학,Kim, Dae-Hyun,Lee, Kwang-Hak 한국재료학회 2010 한국재료학회지 Vol.20 No.2

This study looked at high performance copper-based alloys as LED lead frame materials with higher electrical-conductivity and the maintenance of superior tensile strength. This study investigated the effects on the tensile strength, electrical conductivity, thermal softening, size and distribution of the precipitation phases when Cr was added in Cu-Fe alloy in order to satisfy characteristics for LED Lead Frame material. Strips of the alloys were produced by casting and then properly treated to achieve a thickness of 0.25 mm by hot-rolling, scalping, and cold-rolling; mechanical properties such as tensile strength, hardness and electrical-conductivity were determined and compared. To determine precipitates in alloy that affect hardness and electrical-conductivity, electron microscope testing was also performed. Cr showed the effect of precipitation hardened with a $Cr_3Si$ precipitation phase. As a result of this experiment, appropriate aging temperature and time have been determined and we have developed a copper-based alloy with high tensile strength and electrical-conductivity. This alloy has the possibility for use as a substitution material for the LED Lead Frame of Cu alloy.

Proline and Ammonia Accumulation in the Zoysiagrass Infected with Large Patch

김대현,이복례,이재식,이명,김태환,Kim, Dae-Hyun,Lee, Bok-Rye,Lee, Jae-Sik,Li, Ming,Kim, Tae-Hwan The Korean Society of Grassland and Forage Science 2007 한국초지조사료학회지 Vol.24 No.2

병원균 감염에 의한 식물체내 프롤린과 암모니아의 농도 변화와 그것의 스트레스 생리학적 의미를 구명하기 위하여 Rhizoctonia spp.를 처리 후 라지 펫치에 감염된 잔디의 생육 및 관련 화학적 성분을 감염이 되지 않은 대조구와 비교하였다. 라지 펫치에 감염된 잔디의 뿌리의 건사율은 대조구에 비해 약 30% 증가하였다. 가용성 단백질 농도는 병원균 처리후 6일째 잎의 경우를 제외하고는 라지 펫치 감염에 따른 유의적인 영향이 없었다. 암모니아 농도 역시 라지 펫치에 감염된 잎과 줄기에서 공히 유의적으로 증가하였다. 프롤린 농도는 잎과 뿌리에서 대조구에 비해 각각 3.4 및 4.5배 증가하였다. 이러한 결과들은 잔디에 있어 병원균 감염에 따른 프롤린의 축적은 스트레스 강도를 나타내는 민감한 표지물질로서 의미가 있음을 제시한다. To investigate the response of proline and ammonia to pathogen infection, plant growth and relevant chemical component were examined in large patch-infected or healthy (control) zoysiagrass during 6 days after treatment. Pathogen-infection increased root mortality by 30% compared to control. Soluble protein was not significantly affected by pathogen-infection except in the leaf at day 6. Ammonia concentration also increased significantly in both leaves and roots of pathogen-infected plants. Proline concentration in leaves and roots increased to 3.4- and 4.5-fold, respectively, compared to those of control at day 6. These results suggest that proline accumulation may be a sensitive biochemical indicator representing the stress intensity caused by pathogen infection in zoysiagrass.

DEMS와 H-terminated Si (001) 표면의 상호작용: 제일원리연구

김대현,김대희,박소연,서화일,이도형,김영철,Kim, Dae-Hyun,Kim, Dae-Hee,Park, So-Yeon,Seo, Hwa-Il,Lee, Do-Hyoung,Kim, Yeong-Cheol 한국세라믹학회 2009 한국세라믹학회지 Vol.46 No.4

We performed a density functional theory study to investigate the interaction of DEMS (diethoxymethylsilane) with the H-terminated Si (001) surface. The optimum structure of DEMS was first calculated by a first principles study. The dissociation probability of the O-C bond of DEMS was higher than the other seven bonds based on the bond energy calculation. When the fragmented DEMS groups reacted with the H-terminated Si (001) surface, it was the most favorable among the eight reactions to form a bond between the Si atom on the surface and the O atom of a fragmented DEMS group (($C_2H_5O$)Si($CH_3$)(H)-O-) by forming a $C_2H_6$ as by-product.

The Oxidative Stress Induction and Response of Antioxidative Enzymes in the Large Patch-Infected Zoysiagrass I. Oxidative stress induction

김대현,이복례,이명,김태환,Kim, Dae-Hyun,Lee, Bok-Rye,Li, Ming,Kim, Tae-Hwan The Korean Society of Grassland and Forage Science 2007 한국초지조사료학회지 Vol.21 No.2

한국형 잔디에 있어 병원성 (라지 팻치) 감염이 산화적 스트레스의 발현에 미치는 영향을 규명하기 위해 라지 팻치에 감염된 잔디의 생육, 뿌리 건사율, 과산화수소 농도 및 지질과산화 정도를 감염이되지 않은 대조구와 비교하였다. 처리 후 6일 동안 이틀간격으로 잎과 뿌리 시료에 대해 각각 분석하였다. 라지 팻치에 감염된 잔디 뿌리의 건사율은 대조구에 비해 약 30% 증가하였다. 건물 함량은 4일째까지는 유의적인 차이가 없었으며 6일차에서만 라지 팻치 감염에 따라 잎에서 14% 뿌리에서 20% 각각 감소하였다. 과산화수소의 농도는 라지 팻치에 감염된 잎에서 초기 2일 동안 약 28%의 높은 증가를 하였다가 이후 서서히 감소하여 6일차에는 대조구에 비교하여 11% 낮은 수준이었다. 뿌리에서는 감염에 따른 과산화수소의 증가가 뚜렷하여 6일차에는 대조구에 비해 약 1.7배 높았다. 지질과산화 정도는 잎의 경우, 라지 팻치 감염에 따라 초기 4일간 지속적으로 증가하다가 이후 정체하였으며 뿌리에서는 초기 2일간의 증가가 뚜렷하였다. 이러한 결과들은 잔디에 있어 라지 팻치 감염은 산화적 스트레스를 유도하며, 잎과 뿌리 조직간에 산화적 스트레스 발현정도 및 역동성은 차이가 있음을 보여준다. To investigate the effect of large patch infection on oxidative stress induction, growth, $H_2O_2$ concentration and lipid peroxidation were compared between pathogen-infected and healthy (control) zoysiagrass. The sampling for leaves and roots were carried out every 2 days for a period of 6 days. Pathogen-infection increased root mortality by 30% compared to control. Dry mass was not significantly affected by pathogen-infection until day 4, but significant decreases in both leaves (-14%) and roots (-20%) were observed at day 6. The $H_2O_2$ concentration in pathogen-infected leaves rapidly increased within the first 2 days(+28%) and then slightly decreased. The increase of $H_2O_2$ in pathogen-infected roots was distinct, showing 1.7-fold higher level than control at day 6. The extent of lipid peroxidation caused by pathogen-infection continuously increased for the first 4 days. This was then stagnated until day 6. In roots, the significant increase of lipid peroxidation was observed only at day 2. These results indicate that large patch-infection induces oxidative stress, and that the oxidative stress responsive pattern was plant organ specific.

센서 네트워크에서 연결 지속성 향상 가능한 새로운 클러스터링 기법에 관한 연구

김대현,김진묵,이경오,Kim, Dae-Hyun,Kim, Jin-Mook,Lee, Kyung-Oh 한국정보처리학회 2008 정보처리학회논문지 C : 정보통신,정보보안 Vol.15 No.2

센서 네트워크 환경에서 기존에 제안된 많은 라우팅 기법들 중에서 대표적인 LEACH 기법은 클러스터링 기반의 연구방법이다. 이는 많은 센서들로 구성된 센서 네트워크 그룹을 효과적으로 관리하기 위해서 제안된 기법이다. 하지만 이때 클러스터 단위의 그룹을 관리하기 위한 클러스터 헤더에 대한 에너지 잔류량을 고려하지 못한 단점으로 인해 데이터 전송 도중 클러스터 그룹이 파괴되는 문제가 발생할 수 있다. 이에 본 논문에서는 이러한 문제를 해결하고자 클러스터 그룹에 대한 관리를 수행하는 새로운 클러스터링 기법에 대해서 제안하고자 한다. 본 논문에서 제안한 기법을 이용하여 클러스터 그룹의 연결지향성도 향상되었고 데이터 전송과 처리에 있어서 지연 시간도 감소함을 실험 결과를 통해 알 수 있었다. The LEACH is a study method of a clustering base that was representative in many routing techniques that was suggested in sensor network environment. This is suggested technique to manage the sensor network group which consisted of many sensors in efficiency. However, it does not consider energy remaining quantity of the cluster header to manage cluster group, the problem where the cluster group is able to destroyed on the middle which transmits data. We are going to propose to solve such a problem by this paper for new clustering technique to accomplish management for a cluster group. It uses the technique which it proposes from the dissertation which it sees and are to the data transfer and the control also the connection directivity of the cluster group to improve also the lag time diminishes, test result it will lead and the possibility which it will know it was.

Superquadric과 하나의 Z-버퍼 CSG 렌더링 알고리즘을 기반한 3차원 물체 형상 모델링

김대현(Dae-Hyun Kim),현대환(Dae-Hwan Hyeon),이선호(Sun-Ho Lee),최종수(Jong-Soo Choi) 한국통신학회 1999 한국통신학회 학술대회논문집 Vol.1999 No.11

황점볼락 난소 발달에 따른 혈중 성호르몬과 난황단백전구체의 변동

김대현(Dae Hyun Kim),정지현(Jee Hyun Jeong),윤성종(Seong Jong Yoon),황형규(Hyung Gue Hwang),이윤호(Yoon Ho Lee),김대중(Dae Jung Kim) 한국수산과학회 양식분과 2009 韓國養殖學會誌 Vol.22 No.1

제주도 산림자원 현황과 이용 가능성

김대현 ( Dae Hyun Kim ),이성기 ( Sung Gie Lee ),정영교 ( Young Gyo Chung ),정진현 ( Jin Hyun Jeong ) 한국녹지환경디자인학회 2008 녹지환경학회지 Vol.4 No.2

Within the forest inventory of Jeju, the national forest has been rich relative to the average national inventory; however, the private forest has formed merely half of the average national area, and the circumstances for forest management were also demonstrated to be poorer than those of the average national forest management. In the organization of age classes, the rate of schonungen kulturen is relatively lower. Thus, it will lead to an unbalanced growth in the forest and hurt its stability, provided that there is no improvement in the age class` structure, which would make it hard to begin sustainable forest management (SFM). Also, the acreage of forest owned by private forest owners was shown to be only half of the national average. Therefore, it appears to be necessary to introduce collectivism into forest management. The forest management plan establishment rate is merely 1.7%, and it is supposed to create active support for building forestry management plans. After analysis, it was decided to pursue the extension of the forestation area, which is only about an average yearly 100ha, for the forestation of a sustainable forest inventory. It would also be necessary in the forestation of tree species to conduct forest management in consideration of sightseeing by selecting tree species specified for local features. The area in Jeju appropriate for tending as a forest proved to be 2,495~3,209ha, and the producible growing stock proved to be 41,717~62,577m3.

Proline and Ammonia Accumulation in the Zoysiagrass Infected with Large Patch

Dae Hyun Kim(김대현),Bok Rye Lee(이복례),Jae Sik Lee(이재식),Ming Li(이명),Tae Hwan Kim(김태환) 韓國草地學會 2007 한국초지조사료학회지 Vol.27 No.1

병원균 감염에 의한 식물체내 프롤린과 암모니아의 농도 변화와 그것의 스트레스 생리학적 의미를 구명하기 위하여 Rhizoctonia spp.를 처리 후 라지 펫치에 감염된 잔디의 생육 및 관련 화학적 성분을 감염이 되지 않은 대조구와 비교하였다. 라지 펫치에 감염된 잔디의 뿌리의 건사율은 대조구에 비해 약 30% 증가 하였다. 가용성 단백질 농도는 병원균 처리후 6일째 잎의 경우를 제외하고는 라지 펫치감염에 따른 유의적인 영향이 없었다. 암모니아 농도 역시 라지 펫치에 감염된 잎과 줄기에서 공히 유의적으로 증가하였다. 프롤린 농도는 잎과 뿌리에서 대조구에 비해 각각 3.4 및 4.5배 증가하였다. 이러한 결과들은 잔디에 있어 병원균 감염에 따른 프롤린의 축적은 스트레스 강도를 나타내는 민감한 표지물질로서 의미가 있음을 제시한다. To investigate the response of proline and ammonia to pathogen infection, plant growth and relevant chemical component were examined in large patch-infected or healthy (control) zoysiagrass during 6 days after treatment. Pathogen-infection increased root mortality by 30% compared to control. Soluble protein was not significantly affected by pathogen-infection except in the leaf at day 6. Ammonia concentration also increased significantly in both leaves and roots of pathogen-infected plants. Proline concentration in leaves and roots increased to 3.4- and 4.5-fold, respectively, compared to those of control at day 6. These results suggest that proline accumulation may be a sensitive biochemical indicator representing the stress intensity caused by pathogen infection in zoysiagrass.

Q-switched NdYAG Laser로 과색소반의 호전을 보인 유전 범발성 색소이상증

김대현 ( Dae Hyun Kim ),권혁 ( Hyuk Kwon ),박영립 ( Young Lip Park ),이상훈 ( Sang Hoon Lee ),황규왕 ( Kyu Uang Whang ),조문균 ( Moon Kyun Cho ),이종석 ( Jong Suk Lee ),이성렬 ( Sung Yul Lee ) 대한피부과학회 2009 대한피부과학회지 Vol.47 No.10

Dyschromatosis universalis hereditaria is a rare pigmentary disorder that`s characterized by the presence of both small and irregular sized hyperpigmented and hypopigmented macules in a generalized distribution. The pattern of inheritance is thought to be autosomal dominant, but some sporadic and autosomal recessive inheritance cases have also been reported. We report here on a case of a-15-year old female patient with dyschromatosis universalis hereditaria, which is compatible with autosomal dominant inheritance. The patient presented with numerous small and irregularly sized hyper-and hypopigmented macules on her face, trunk and both the arms and legs, but not on the palms and soles. By analysis of her familial pedigree, we found an autosomal dominant pattern of inheritance. The biopsy specimen taken from the hyperpigmented macules showed increased melanin granules and pigmentation in the basal cell layer of the epidermis. Various therapeutic trials have been introduced to treat these lesions, but there have been few reports of simple effective treatments for the hyper-and hypopigmented lesions. So, we tried treating the hyperpigmented macules with a Q-switched Nd:YAG laser and we obtained a successful result. (Korean J Dermatol 2009;47(10):1166∼1171)