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        검색결과 281

        241.
        2007.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        가압경수로형 원자력발전소의 운영과정에서 발생된 폐수지내 및 의 분포특성을 조사하였다. 표준용액을 사용한 의 회수율 측정결과, 사용한 산의 종류에 관계없이, 3 N-HCl , 주입한 농도 범위에서 의 회수율을 나타내었다. 같은 장치를 사용하여 HTO 표준용액 증류에 의한 의 회수율은 주입한 농도 범위에서 이었다. 습식산화-산용출법에 의한 폐수지의 및 동시분리시, 를 사용했을 때 다른 감마핵종에 의한 방해가 없었으며, 포집액이 섬광제와 잘 혼합되었다. 그러나 3 N-HCl을 사용했을 때 포집용액에서 및 등의 감마핵종이 검출되었다. 또한 Sample Oxidizer에 의한 포집용액에서도 및 등이 검출되었으며, 포집용액에서는 이 검출되었다. 폐수지의 총 함량중 약 70% 이상이 무기 탄소로 확인되었다. 30개 폐수지 시료중 8개 고방사능 폐수지의 및 의 평균농도는 각각 이었으며 22개 저방사능폐수지에서는 각각 이 검출되었다. 고방사능 폐수지의 평균 비는 28로 저방사능 폐수지의 0.70에 비해 높게 나타났으며, 및 의 농도는 서로 비례하는 경향을 보였다.
        4,000원
        242.
        2006.09 구독 인증기관·개인회원 무료
        We found that the """interface reaction between Ni-based alloy bond, diamond, and steel core is very critical in bond strength of diamond tool. None element from metal bond diffuses into the steel core but the Fe element of steel core was easily diffused into the bond. This diffusion depth of Fe has a great effect on the bonding strength. The Cr in steel core accelerated the Fe diffusion and improved the bond strength, on the other hand, carbon decreased the strength. Ni-based alloy bond including Cr was chemically bonded with diamond by forming Cr carbide. However, the Cr and Fe in STS304 were largely interdiffused, the strength was very low. The Cr passivity layer formed at surface of STS304 made worse strength at commissure in brazing process.
        243.
        2006.09 구독 인증기관·개인회원 무료
        Currently Chemical Mechanical Planarization (CMP) has become an essential step in the overall semiconductor wafer fabrication technology. Especially the CMP pad conditioner, one of the diamond tools, is required to have strong diamond cohesion. Strong cohesion between diamond and metal matrix prevents macro scratch on the wafer during CMP Process. Typically the diamond tool has been manufactured by sintered, brazed and electro-plated methods. In this paper, some results will be reported of cohesion between diamond and metal matrix of the diamond tools prepared by three different manufacturing methods. The cohesion force of brazed diamond tool is found stronger than the others. This cohesion force is increased in reverse proportion to the contact area of diamond and metal matrix. The brazed diamond tool has a strong chemical combination of the interlayer composed of Cr in metal matrix and C in diamond, which enhance the interfacial cohesion strength between diamonds and metal matrix.
        244.
        2006.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        5,200원
        245.
        2006.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        원자력 발전소의 증기발생기 슬러지 중에서는 이온교환수지가 발견되어서는 안 된다. 원자력 발전소의 증기발생기 슬러지 시료 중에서 발견되어 이온교환수지 입자로 의심되는 구형 입자들의 특성을 측정하였다. 미세조작기술을 이용하여 광학현미경으로 입자 크기 분포를, EPMA로 구형입자의 성분을, 그리고 IR 분광 스펙트럼 비교에 의하여 이온교환수지 여부를 조사하였다. 슬러지의 입자 크기는 1 내지 이었으나 구형 입자는 이었다. 슬러지의 주요 불순원소가 Si, Al, Mn, Cr, Ni, Zn, 그리고 Ti이었으나 구형 입자는 Si, Cu, Zn 이었다. 주성분은 두 경우 모두 철이었다. 구형 입자의 IR 분광스펙트럼은 증기발생기 취출수 정화계통에서 사용하는 이온교환수지의 스펙트럼과 비교했을 때 서로 일치하지 않음을 보여주었다. 이 결과들은 증기발생기 슬러지 시료 중에서 발견된 구형 입자가 이온교환수지는 아니며 일반적인 슬러지가 생성되는 과정에서 작은 슬러지 입자들이 크게 뭉쳐서 생성된 것임을 나타내고 있다.
        4,000원
        247.
        2004.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The effects of intra-peritoneal injection of inorganic mercury on haemato-logical parameters and hepatic oxidative stress enzyme activities were studied in common carp, Cyprinus carpio. The fish were injected thrice intra-peritoneally with mercuric chlori
        4,000원
        248.
        2004.12 구독 인증기관 무료, 개인회원 유료
        Efficiency of somatic cell nuclear transfer was investigated in mice. First, oocyte activation was induced by SrCl₂, and the rate of development was compared with embryos from normal fertilization. Although more than one half of SrCl₂-treated oocytes developed to blastocysts (146/262, 55.7%), the rate of blastocyst formation was significantly lower than normal fertilization controls (59/79, 74.6%). Second, enucleation of oocytes was performed using Polscope that enables non-invasive visualization of metaphase spindles. Such approach could not only avoid damage of oocytes during an exposure to UV light often employed in conventional enucleation procedures, but could also assure the removal of nuclei from all oocytes operated because of monitoring the location of spindles during an entire process of enucleation. Morphologically normal blastocysts were obtained from the transfer of cumulus cell nuclei into enucleated oocytes. However, the rate of development into the blastocyst stage was still low (4/93, 4.3%). This reflects that the nuclear transfer procedure used in this study was not sufficiently optimized, and other factors may also impact greatly the efficiency of nuclear transfer. Including an induction of oocyte activation and method of enucleation tested in this study, a lot more elements are remained to be optimized to improve the efficiency of somatic cell nuclear transfer in mice.
        3,000원
        252.
        2004.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        NIPS 시스템은 중성자 핵반응 결과 방출되는 즉발 감마선을 정량적으로 측정하는 장치이며 고체 및 액체 폐기물 중 존재하는 다양한 원소를 비파괴적으로 분석할 수 있는 장점이 있다. 본 연구에서는 NIPS 시스템에 이용된 고순도반도체 검출기의 계측효율을 Ba 및 Eu 방사성 동위원소 선원과 Cl(n, ) Cl 핵반응 시 발생되는 즉발감마선을 이용하여 80 keV에서 8 MeV까지 넓은 영역에 대하여 구하였다. Cl(n, ) Cl 핵반응을 이용한 고에너지 감마선의 계측효율은 즉발감마선의 방사능 값을 정확히 알 수 없기 때문에 저 에너지 영역에서 정확히 알고 있는 검출기 효율곡선에 규격화시켜 전 에너지 영역에서의 효율보정곡선을 구하였다. 또한 KCl 표준용액에 Cf 중성자 선원을 조사시켜 표준용액으로부터 방출되는 즉발 감마선을 고순도반도체 검출기로 측정하고 광대역 계측효율 곡선을 이용하여 수용액 시료에서의 평균 열중성자 속을 예측하였다. NIPS 측정시스템은 주변 재료 물질의 핵반응으로 방출되는 감마선 background를 줄이기 위해 두 개의 고순도반도체 검출기를 이용한 동시계수 장치가 고안되었으며, 동시계수 모드에서의 계측효율도 함께 고려되었으며, 표준선원을 이용하여 전 계수 또는 동시계수모드에서의 background에 대한 측정감도를 비교하였다.다.
        4,000원
        254.
        2003.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Phenanthrene, one of Polycyclic aromatic hydrocarbons with three aromatic rings, is a ubiquitous contaminant in the environment. Phenanthrene has been identified in ambient air, drinking water and sediment. We examined the effect of phenanthrene on steroi
        4,000원
        255.
        1991.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        외연적 유한요소법은 벡터처리에 적합한 구조를 가지고 있어 벡터컴퓨터를 이용하면 기존의 스칼라 컴퓨터에서보다 휠씬 빠르게 해석을 수행할 수 있다. 본 논문에서는 memory-to-memory방식의 벡터컴퓨터에서의 외연적 유한요소법의 효율적인 벡터화 방법을 제시하였다. 먼저 벡터컴퓨터의 구조적 특성과 무관하게 적용될 수 있는 일반적인 벡터화 기법을 고찰한 후 memory-to-memory방식의 벡터컴퓨터에 적합한 벡터화 기법을 개발하였다. 개발된 벡터화 기법의 유용성을 확인하기 위해 외연적 유한요소 프로그램인 DYNA3D를 memory-to-memory방식의 벡터컴퓨터인 HDS AS/XL V50에 이식한 결과 스칼라에 비해 2.4배 이상의 성능 향상을 얻을 수 있었다.
        4,600원
        258.
        2012.12 KCI 등재 서비스 종료(열람 제한)
        Carotenoids of squash play an important role in human health by acting as sources of provitamin A or as protective antioxidants. Among the 60 accessions of squash germplasm, fluorescent yellow and yellow types of flesh color got the highest count, followed by the orange, whitish yellow and greenish yellow. The redness and yellowness values of the flesh powder ranged from -2.45 to 86.09 and from 13.77 to 39.80, respectively. While the lightness and the total color difference values of flesh color varied from 67.64 to 86.09 and from 19.77 to 51.79, respectively. Colorimetric values of redness and yellowness showed positive correlation, and the correlation coefficient (r) was as high as 0.7386. The five accessions represented each flesh color types, IT195043 (orange), IT136696 (fluorescent yellow), IT186365 (yellow), IT137963 (whitish yellow), and IT180449 (greenish yellow). The total amount of carotenoid contents was in the order of orange color (104.64 mg/100 g), greenish yellow color (70.82 mg/100 g), fluorescent yellow color (32.41 mg/100 g), yellow color (8.73 mg/100 g), and whitish yellow color (4.73 mg/ 100 g). Both lutein and β-carotene were the predominant pigments of carotenoids, and lycopene was only separated and identified in the orange color flesh. According to the results, colorimetric analysis can aid breeders interested in increasing carotenoid content in squash, which could be accurately measured using a simple, reliable, and cost- and labor-efficient method for the evaluation of carotenoid pigments.
        259.
        2011.12 KCI 등재 서비스 종료(열람 제한)
        Organic and chemical fertilizer amendments are an important agricultural practice for increasing crop yields. In order to maintain the soil sustainability, it is important to monitor the effects of fertilizer applications on the shift of soil microorganism, which control the cycling of many nutrients in the soils. Here, culture-dependent and cultureindependent approaches were used to analyze the soil microorganism and community structure under six fertilization treatments, including green manure, rice straw compost, rapeseed cake, pig mature compost, NPK +pig mature compost, NPK and control. Both organic and chemical fertilizers caused a shift of the cultural microorganism CFUs after treatments. Bacterial CFUs of the organic fertilization treatments were significantly higher than that of chemical fertilization treatments. The DGGE profiles of the bacterial communities of the samples showed that the green manure treatment was a distinct difference in bacterial community, with a greater complexity of the band pattern than other treatments. Cluster analyses based on the DGGE profile showed that rice straw compost and pig mature compost had a similar banding pattern and clustered together firstly. Rapeseed cake, NPK, NPK + pig manure compost and control clustered together in other sub-cluster and clearly distinguished from green manure.
        260.
        2011.12 KCI 등재 서비스 종료(열람 제한)
        In traditional organic rice culture practices, control of weeds is a big problem. This study was conducted to increase the rice production. Results showed that Plant heighl, SPAD, root length and weíght were higher in pot raísed seedling than broadcasting method except number of panicles. High plant density caused reduction in plant height, number of culm and chlorophyll content of the rice. No lodging was observed in both methods. Thickness of third intemode and culm length was more in pot raised see에ings at both sites. When organic material was used rice yield increased by 3.81%. Higher rice production (10%) was recorded in the fields planted with pot raised seedlings. From the above study it could be conclude that the pot raised seedlings perform better than the seedlings raised by broadcasting methods.