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        검색결과 297

        161.
        2006.09 구독 인증기관·개인회원 무료
        We reported a P/M soft magnetic material with core loss value of , which is lower than that of 0.35mm-thick laminated material, by using high purity gas-atomized iron powder. Lack of mechanical strength and high cost of powder production are significant issues for industrial use. In order to achieve both low core loss and high strength by using inexpencive powder, the improvement of powder shape and surface morphology and binder strength was conducted. As the result, the material based on water-atomized powder with 80 MPa of TRS and 108 W/kg of core loss (W10/1k) was achieved.
        162.
        2006.09 구독 인증기관·개인회원 무료
        Core loss of soft magnetic powder cores have been focused on to achieve high efficiency of power supplies. In this study the effects of crystal grain size on core loss were investigated by changing heat treatment conditions. It was found that core loss is influenced by crystal grain size because eddy current loss decreased and hysteresis loss increased by making crystal grain size smaller, and it is also influenced by particle size.
        164.
        2006.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Genomic imprinting is defined as parent-of-origin expression of specific genes and may play an important role in embryonal development of mammals. Loss of imprinting(LOI), biallelic expression of the imprinted genes, have been observed in a variety of human tumors and syndromes. H19, a paternally imprinted gene, is transcribed as an untranslated RNA that serves as a riboregulator. LOI of H19 is observed in a variety of human malignancies. In this study, LOI of H19 was examined in head and neck squamous cell carcinomas(HNSCCs). Four(28.6%) of the 14 HNSCCs and 8(28.6%) of the 28 inflammatory oral lesions were informative for imprinting analysis of H19. H19 was imprinted in all inflammatory oral lesions, however, 2(50%) of the 4 informative HNSCCs manifested LOI. These data suggest that LOI of the H19 may play a role in the oncogenesis of HNSCC.
        4,000원
        166.
        2006.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        경량 연성구조시스템 중 하나인 막 구조물은 대공간 구조물에 많이 사용되어진다. 막 구조물은 축강성이 강하고 휨강성이 매우 작은 재료를 주 구조재로 사용하기 때문에 다른 구조물과 달리 구조설계에서는 형상해석, 응력-변형해석 그리고 재단도 등의 일련의 과정을 필요로 한다. 재단도의 작성에는 구조물의 크기나 곡률 그리고 재료적 강성에 따라 많은 변수가 작용하며 다른 설계과정과는 매우 다르다. 따라서 일반 구조설계용 프로그램은 막 구조물의 구조설계에 부적당하다. 본 연구에서는 막 구조물의 측지선을 이용한 재단도 작성 프로그램을 개발하고, 예제를 통해 재단도 작성결과를 비교 고찰하도록 한다.
        4,200원
        167.
        2005.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The traditional process capability indices Cp, Cpk, Cpm, Cpm+ have been used to characterize process performance on the basis of univariate quality characteristics. Cp, Cpk consider the process variation, Cpm considers both the process variation and the p
        4,000원
        168.
        2005.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        대기환경 중에 존재하는 여러 가지 가스상 성분들을 채취 및 이송시키고자 할 때, 다양한 종류의 튜빙을 사용한다. 이와 같은 튜빙의 사용과 연계된 여러 가지 오차를 분석하기 위해, 악취황 성분들을 이용한 비교분석을 시도하였다. 이를 위해 45cm 길이로 6가지 재질의 튜빙을 선택하여, 각 튜빙별 손실특성을 평가하고자 하였다. 이를 위해, 10ppb 농도의 표준시료를 준비하고, 이를 튜빙에 통과시켜 준 후, 튜빙을 통과한 전후에 검출되는 농도를 비교하는 방식으로 손실율을 산출하였다. 이러한 비교의 목적상, 환원황 성분에 가장 우수한 회수율을 보이는 Silco Steel 튜빙을 통과한 결과를 기준 검량선으로 설정하고 여타 튜빙에 대한 회수율을 비교하였다. 그 결과 Teflon 튜빙에서는 4가지 황화합물 모두 90% 이상의 높은 회수율을 보일 정도로 양호한 결과를 보였다. 이에 비해 스테인레스나 브래스 재질의 경우, 저분자 황성분에 해당하는 H2S, CH3SH에서 상당한 손실을 보였다. 반면 실리콘 튜빙의 경우, 고분자 성분에 해당하는 DMS, DMDS에서 큰 손실을 보였다. 결과적으로 황화합물의 종류나 튜빙의 재질에 따라 RSC의 손실은 다양한 형태로 나타나는 것을 확인할 수 있다.
        4,000원
        169.
        2005.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The main objective of this paper is to search whether containment vessel's best pressure may increase until how long when loss of coolant accident (LOCA) happened in containment vessel of Ulchin nuclear power plant 1 and 2. Another goal of this research is to find the influential factors that increase containment vessel pressure. Model for this research is Ulchin nuclear power plant 1 with 10 cycles. Data were collected by simulator of Ulchin nuclear power plant 1 and design of experiment was used for data analysis. For the experiment, seven factors that are going to influence in containment vessel pressure were chosen. It was found that fatter which influences in early rise of containment vessel pressure after LOCA is only explosion size. Also, containment vessel's best pressure (3.74 bar.a) was much lower than limit (4.86 bar.a) of FSAR (Final Safety Analysis Report).
        4,800원
        170.
        2005.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We investigate the spectral energy distributions (SEDs) of low mass-loss rate O-rich asymptotic giant branch (AGB) stars using the infrared observational data including the Infrared Space Observatory (ISO) data. Comparing the results of detailed radiative transfer model calculations with observations, we find that the dust formation temperature is much lower than 1000 K for standard dust shell models. We find that the superwind model with a density-enhanced region can be a possible alternative dust shell model for LMOA stars.
        3,000원
        173.
        2005.05 구독 인증기관 무료, 개인회원 유료
        Process capability indices are widely used in industries and quality assurance system. When designing the parameter on the multiple quality characteristics, there has been a study for optimization of problems, but there has been few former study on the possible conflicting phenomena in considertion of the correlations among the characteristics. To solve the issue on the optimal design for muliple quality characteristics, the study propose the expected loss function with cross-product terms among the characteristics and derived range of the coefficients of terms. Therefore, the analysis have to be required a multivariate statistical technique. This paper introduces to multivariate capability indices and then selects a multivariate process capability index incorporated both the process variation and the process deviation from target among these indices under the multivariate normal distribution. We propose a new multivariate capability index MCpm using quality loss function instead of the process variation and this index is compared with the proposed indices when quality characteristics are independent and dependent of each other,
        5,400원
        174.
        2005.05 구독 인증기관 무료, 개인회원 유료
        TPM(Total Productive Management) that is enforcing introducing more than 80% in domestic manufacturing industry is using total plant efficiency by the evaluation index, and as a result, can see a lot of examples that plant productivity is increased. This study's purpose centers total productive management activities that is management system for total plant efficiency's maximization, plant information system that total productive management activities factor that is enforcing in manufacturing industry can develop evaluation model that can evaluate qualitative activities by quantitative activities in process that maximize total plant efficiency wishes to do design.
        4,000원
        176.
        2004.11 구독 인증기관 무료, 개인회원 유료
        Process capability indices are widely used in industries and quality assurance system. When designing the parameter on the multiple quality characteristics, there has been a study for optimization of problems, but there has been few former study on the possible conflicting phenomena in considertion of the correlations among the characteristics. To solve the issue on the optimal design for multiple quality characteristics, the study propose the expected loss function with cross-product terms among the characteristics and derived range of the coefficients of terms. Therefore, the analysis have to be required a multivariate statistical technique. This paper introduces to multivariate capability indices and then selects a multivariate process capability index incorporated both the process variation and the process deviation from target among these indices under the multivariate normal distribution. We propose a new multivariate capability index MCpm using quality loss function instead of the process variation and this index is compared with the proposed indices when quality characteristics are independent and dependent of each other.
        4,200원
        178.
        2004.04 구독 인증기관 무료, 개인회원 유료
        This paper investigates the mathematical model of multi-server retrial queueing system with the Batch Markovian Arrival Process (BMAP), the Phase type (PH) service distribution and the finite buffer. The sufficient condition for the steady state distribution existence and the algorithm for calculating this distribution are presented. Finally, a formula to solve loss probability in the case of complete admission discipline is derived.
        4,000원