• Journal of the Korean institute of surface engineering
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• v.48 no.6
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• pp.335-342
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• 2015

Recently, the production of oil and gas at the arctic ocean and offshore has been growing. Accordingly, S500 steel with the high tensile strength and excellent toughness has been used and flux cored wire that can be welded to the S500 has been required. In this study, we carried out observation of microstructures, mechanical properties and CTOD (crack tip openning displacement) in the weld zone that GMA (gas metal arc) welded with different component of $TiO_2$ flux core wire (the main components, rutile or Ti-slag) for S500 steel. Weld zone produced with Ti-slag flux cored wire has formed a enough acicular ferrite and shown excellent impact toughness at $-40^{\circ}C$, tensile strength at room temperature and CTOD at $-20^{\circ}C$. As a result, the developed flux cored wire was suitable for S500 steel.

• Korean Journal of Microbiology
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• v.49 no.3
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• pp.282-285
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• 2013

Microbial diversities in the 300 m and 500 m deep seawaters near Goseong, Gangwon Province (South Korea), were investigated. Pyrosequencing of 16S rRNA genes of marine microbes resulted in 19,474 reads from the 300 m deep seawaters, which consisted of Alphaproteobacteria (57.41%) and Gammaproteobacteria (38.85%), and 82,806 reads from the 500 m deep seawaters, which consisted of Gammaproteobacteria (99.64%) mostly. Rhodobacterales (57.31%) were dominant in the 300 m deep seawaters, but Alteromonadales (45.65%) and Oceanospirillales (34.61%) were dominant in the 500 m deep seawaters. On the bases of operational taxonomic units and diversity indexes (Shannon and Simpson), biodiversity of marine bacteria in the 500 m deep seawaters was shown to be higher than that in the 300 m deep seawaters.

• Journal of Environmental Health Sciences
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• v.23 no.2
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• pp.12-23
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• 1997

The biosynthesis of galactolipid, galactose and the fatty acid composition in E. cdi and B. subtills treated with potassium dichromate(PD, 500 ppm, 500 ppm), potassium chromate(PC, 500 ppm, 500 ppm), cobalt chloride(CC, 100 ppm, 10 ppm) and methylmercuric chloride(MC, 100 ppm, 10 ppm) during the culture were analyzed to compare with the control. The growth rate of cells, the contents of monogalactosyldiglyceride(MGDG), digalactosyldiglyceride(DGDG) and total lipid in the metal compound treatments were lower as compared with the control. And too, the contents of galactose utilized for the biosynthesis of galactolipids in these strains in the various metal compounds treatments were inhibited. The fatty acids used for the MGDG and DGDG formation in E. coli and B. subtills treated with each metal compounds during the culture were showed to the variant compositional change.

• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.951-954
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• 2003

본 논문에서는 고속. 저전력에 적합한 개방 구조를 갖는 8-비트 500Msmaples/s 2-Step ADC 를 제안하였다. 500Msmaples/s 의 고속 동작을 위해서 기존의 M-DAC을 이용한 폐쇄 구조 대신 개방형 구조를 사용하였다. 이와 더불어 저전력을 구현하기 위해서 analog-latch 를 제안하여 동적 동작을 수행시킴으로써 전력 소모를 줄였으며 , mux 의 구현 시 reset switch를 이용하여 로딩 시간을 개선함으로써 high-speed 에 적합하도록 설계하였다. 제안된 ADC 는 1-poly 6-metal 0.18um CMOS 공정을 이용하였으며 1.8V 전원 전압을 이용하여 250mW 의 전력을 소모하며 500M 샘플링 주파수에서 120MHz 신호 입력 시 7.6 비트의 ENOB를 얻을 수 있었다.

• The Korean Journal of Financial Management
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• v.13 no.1
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• pp.341-357
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• 1996

Some empirical studies have shown that asset prices respond to announcements of economic news, however, others also have found little evidence. This study assesses how market participants of the S&P 500 Index Futures reacted to the U.S. economic news announcements. For this purpose, using a GARCH (Generalized Autoregressive Conditional Heteroscedasticity) model, we use several U.S. news variables, its each surprise component and interest rates. We find that some economic news variables affected significantly on the S&P 500 Index Futures. In other words, we find that weekend variable, lagged volatility, and surprise component of trade deficit increased level of volatility. However, interest rate, M1, unemployment announcements caused the variance of the S&P 500 Index Futures to reduce, and each of the surprise component of M1 and trade deficit increased it. The result suggests that resolution of uncertainty, through economic news announcement, while, in some cases, causes market participants to reduce their forecast of volatility, a large difference between the market's forecast and the realization of the series causes the volatility to increase.

• Asian-Australasian Journal of Animal Sciences
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• v.2 no.2
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• pp.77-84
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• 1989

Twenty-four Hereford steers, 22 months old and a mean liveweight (${\pm}\;s.e.$) of $250\;{\pm}\;7\;kg$ were used in an experiment to evaluate over 42 days two rates of copra meal supplementation to cattle on a low N ($8.6\;{\pm}\;0.9$ g N/kg dry matter (DM)), low digestible ($45\;{\pm}\;5.2%$ DM) native pasture hay. Steers given the two rates (500, 1000 g/steer/day; i.e. 500C, 1000C) were compared to steers on a non-supplemental diet and to the effects on steers of supplemental urea (30g/steer/day; 30U) or with copra meal (500 g/steer/day; 500C.U), or of cottonseed meal (500 g/steer/day; 500S). Liveweight change was increased (P<0.01) by all of the supplements except by supplemental urea. The most effective treatment, 1000C, increased significantly (P<0.01) liveweight change (946 g/day) in steers above all supplements except those steers given 500C.U (718 g/day). Hay intake per unit liveweight was increased (P<0.05) by 7% by the 30U and 500C.U treatment, and by 9% by 500C; this group having the highest supplements, being greatest (P<0.05) for the 1000C group (6.0 g feed intake/g gain) and least for the 500S supplemented group (11.5 g/g gain). Efficiency was lowest (18.6 g/g gain) for the non-supplemented steers on the basal hay diet. Copra meal N was less degradable (i.e. 29%) in nylon bags over 15 hours in the rumen than was cottonseed meal N (37%), and rumen ammonia concentrations were lower (P<0.05) in cattle supplemented with copra meal (25, 27 mg N/L) than in cattle given urea (36 mg N/L) or cottonseed meal (39 mg N/L). It is concluded that copra meal at a daily rate of 500 g/head, and with rumen soluble nitrogen from urea, is an effective supplement for improving growth of cattle on a low quality forage.

• Korean Journal of Food Science and Technology
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• v.23 no.2
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• pp.205-211
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• 1991

Ethanol extracts of amur cork, elm root, plantain and dandelion which are edible and can be mass produced at farm were examined their inhibitory activity against food spoilage microorganisms at their concentrations and the extracts were fractionated by some solvents with checking effective fractionate. Above $500{\sim}2000\;ppm$ of the extracts inhibited completely the test microorganisms with a few exception. One thousand ppm of amur cork exract inhibited B. cereus completely. L. mesenteroides by 500 ppm of amur cork and 2000 ppm of elm root and plantain showed a pretty good inhibition. The extracts which showed good inhibition to the test microorganisms were fractionated with chroloform, ethylacetate, butanol and water in order and the fractionates of butanol and chroloform showed comparetively higher inhibition than others generally. Inhibition rate of each fractionate were as follows ; B. cereus was inhibited completely at 500 ppm of chroloform fraction, and 1000 ppm of ethyl acetate and butanol and L. mesenteroides was 500 ppm of butanol fraction. P. fluorescens was inhibited partly by 500 ppm of butanol and ethyl acetate fraction.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.2149-2152
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• 2005

가속기 연구소에서 500kV 고전압 다중채널 다중갭(MGMC) 스위치를 개발하였다. 이 다중 채널 다중 갭 스위치는 개스를 채우는 방식으로 자발 방전전압을 증가 시킬 수 있는 10단의 갭으로 구성이 되어 있다. 멀티갭 스위치의 구조는 스위치의 자체 인덕턴스를 증가시키는 결과를 가져온다. 따라서 이러한 문제점을 해결하기 위하여 다중채널을 사용하여 인덕턴스를 줄이는 스위치로 구조를 설계하였다. 제작된 스위치는 500kV의 Marx generator를 사용하여 시험을 하였다. 본 논문에서는 개발된 스위치 선계 및 스위치의 특성에 대하여 알아보고자 한다.

• Journal of Intelligence and Information Systems
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• v.2 no.2
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• pp.43-54
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• 1996

Financial markets are operating 24 hours a day throughout the world and interrelated in increasingly complex ways. Telecommunications and computer networks tie together markets in the from of electronic entities. Financial practitioners are inundated with an ever larger stream of data, produced by the rise of sophisticated database technologies, on the rising number of market instruments. As conventional analytic techniques reach their limit in recognizing data patterns, financial firms and institutions find neural network techniques to solve this complex task. Neural networks have found an important niche in financial a, pp.ications. We a, pp.y neural networks to Standard and Poor's (S&P) 500 stock index futures trading to predict the futures marker behavior. The results through experiments with a commercial neural, network software do su, pp.rt future use of neural networks in S&P 500 stock index futures trading.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.167-167
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• 2011

한국표준과학연구원에서는 국제표준화기구에서 제정한 국제규격(ISO, PNEUROP, DIN, JIS, AVS 등)에 기반을 둔 터보분자펌프의 특성평가시스템을 자체적으로 설계/제작 하였고, 터보분자펌프 1,000 L/s 급의 Database를 구축하였다. 이것을 토대로 특성평가시스템의 신뢰성 확인과 Feedback을 통한 시제품 개발 및 평가지원을 위해 터보분자펌프 2,500L/s 급의 Database를 구축한다. 터보분자펌프의 배기성능을 나타내는 가장 중요한 항목인 배기속도는 분자류 영역에 따라 상이한 가스($N_2$, He)를 사용하여 Throughput method와 Orifice method 두 가지 방법을 병행하여 측정한다. 측정함에 있어서 측정게이지, 유량계 및 Orifice conductance의 불확도에 의하여 배기 속도에 많은 측정오차를 포함하고 있다. 측정 오차를 줄이기 위하여 1% 이상의 안정성과 4%의 오차만을 허용하는 자전 회전자게이지(SRG)와 $10^{-3}$ mbar-L/s 영역까지의 유량 주입범위를 가지는 불확도 ${\pm}$3%의 정적형 유량시스템(CVFM)을 사용하였다. Orifice method의 경우 고진공영역으로 진입할수록 커질 수밖에 없는 배기속도 측정 불확도를 최소화하기 위해 검증된 유량을 이용한 Conductance 값을 제시하여 두 방법에서 얻은 배기속도의 불연속적인 문제를 해결한다. 본 연구에서는 2,500 L/s 급 터보분자펌프는 무거운 기체 $N_2$와 가벼운 기체 He을 사용하여 압축비의 변화와 분자류 영역에 따른 배기속도 변화를 연구하고, 2,500 L/s 급 터보분자펌프의 측정능력을 검증한다. 차후에 배기속도뿐만 아니라 소비전력, 소음, 진동, 온도 등의 특성평가의 전반적인 사항을 평가하여 터보분자펌프 2,500 L/s 급의 database를 완비해간다. 터보분자펌프 특성평가시스템을 사용한 1,000 L/s 급과 2,500 L/s 급 특성 Data를 비교, 분석하여 신뢰성 파악 및 표준화 방안을 개발하고, 고진공펌프 개발 주체와의 feedback 지원 기능의 infra를 구축한다.