• 생태와환경
• /
• 제34권1호통권93호
• /
• pp.20-29
• /
• 2001

순수 배양한 남조류 3종 (Microcystis aeruginosa, Anabaena flos-aquae, Oscillatoria agardhii)을 대상으로 식물플랑크톤에 의한 체외배출 용존유기탄소(extracelluar dissolved organic carbon:EOC)의 배출양상, 화학적성분, 자외선흡광 특성을 연구하였다. EOC의 화학적성분은 XAD-8, 양이온, 음이온수지를 이용하여 소수성 산 (hydrophobic acids; AHSs), 소수성 중성 (hydrophobic neutrals: HoNs), 친수성 산 (hydrophilic acids; HiAs), 친수성 염기 (hydrophilic bases; HiBs), 그리고 친수성 중성 (hydrophilic neutrals; HiNs)으로 분류하였다. 3종의 남조류로부터 배출된 EOC의양과 화학적조성은 종마다 상이하였고, 조류의 성장단계에 따라서도 다르게 나타났다. HiAs성분은 남조류가 배출한 EOC의 가장 많은 부분(25${\sim}$92%)을 차지했고, 정체기로 갈수록 HiAs성분이 차지하는 비율이 감소하였다. 반면, HiBs와 HiNs 성분은 정체기로 진행될수록 비율이 증가하였다. 특히 HiNs성분은 성장초기에는 거의 배출되지 않다가 정체기에서는 전체 EOC의 상당한 부분을 차지하였다 (M. aeruginosa: 44%, A. flos-aquae: 28%). AHSs성분은 M. aeruginosa에서 0.2${\sim}$2.5%로 매우 작았지만, A. flos-aquae(8.7${\sim}$16%)와 O. agardhii (7.5${\sim}$16%)에서는 상당한 부분을 차지했다. 그러나 AHSs의 배출은 M. aeruginosa와 O. agardhii에서 성장이 진행될수록 증가한 반면, A. flos-aquae에서는 반대의 경향을 보였다. 남조류에 의해 배출된 EOC의 자외선흡광 특성도 종에 따라 상이한 결과를 보였다. 본 연구의 결과는 남조류의 종과 성장단계에 따라 배출되는 용존유기물의 특성이 다르다는 것을 시사한다.

• 한국데이타베이스학회:학술대회논문집
• /
• 한국데이타베이스학회 1997년도 International Conference MULTIMEDIA DATABASES on INTERNET
• /
• pp.393-404
• /
• 1997

1. HiWEB 서비스 $\textbullet$ 의의 HiWEB서비스는 95년도 공공DB개발사업의 일환으로 과거 텍스트 기반의 DB 에서 탈피하여 한국통신과 한국PC통신이 공동 개발한 국내최초의 멀티미디어 DB로서 그 의의를 가지고 있다. $\textbullet$ 접속경로 01410(01411)접속 1.HiTEL INFOSHOP $\longrightarrow$99. Web서비스 $\longrightarrow$l.HiWEB 인터넷 직접접속 http : //hiweb. kornet. nm. kr $\textbullet$ 구성 내용 NeoGate : 인터넷 홈쇼핑 서비스 WebTheater: 연극/영화/비디오/음악 등 문화정보 서비스 WebCollege： 토익/생활영어 등 교육정보 서비스 대화방/게시판 등 각종 BBS기능 추가 개발중 2. 국내외 인터넷 쇼핑몰 현황 1) 해외 $\textbullet$ '97년 전자상거래 사업규모 80억 달러 추정(Forrester Research) -'96년 대비 10배 증가/2002년에 서비스의 총가치 3270억 달러 예상 $\textbullet$ Amazon(1 천 8백만 달러/96년), Cdnow(6백만달러/96년) 등이 유명 2) 국내 $\textbullet$ 인터파크, 인터넷백화점(롯데)을 선두로 우후죽순격으로 생겨난 인터넷 쇼핑몰간에 치열한 경쟁체제가 구축돼가는 전자상거래(인터넷홈쇼핑)의 초기단계이다.(중략)

• 한국표면공학회:학술대회논문집
• /
• 한국표면공학회 2016년도 추계학술대회 논문집
• /
• pp.3-32
• /
• 2016

High power impulse magnetron sputtering (HiPIMS) technique has been developed for more than 15 years. It is characterized by its ultra-high peak current and peak power density to obtain unique thin film properties, such as high hardness, good adhesion and tribological performance. However, its low deposition rate makes it hard to be applied in industries. In this work, the development of HiPIMS system and integration of radio frequency (RF) or mid-frequency (MF) power supplies were introduced. Effects of duty cycle and repetition frequency on the microstructure, mechanical property, optical and electrical properties of some binary, ternary and quarternary nitride coatings and oxide thin films were discussed. It can be observed that the deposition rate was effectively increased by the superimposed HiPIMS with RF or MF power. High hardness, good adhesion and sufficient wear resistance can be obtained through a proper adjustment of processing parameters of HiPIMS power system.

• Journal of Astronomy and Space Sciences
• /
• 제24권1호
• /
• pp.45-54
• /
• 2007

The relationship between the Galactic magnetic field strength and the gas density has been revisited. A synchrotron continuum emission data at 408 MHz and HI column density provide a good data for such study. But it is difficult to separate the synchrotron emission from the observed 408MHz radio emission, because the 408MHz radio emission has the component from the HI layer, as well as many components from other origins. We have tried to substract the component which is probably not related with HI layer, and present the results. We show that the method presented here is a more refined method than that of Brown & Chang (1983, hearafter BC83) to find the above mentioned relationship, and discuss the existence of such relationship in our Galaxy.

• 천문학회보
• /
• 제41권2호
• /
• pp.40.3-41
• /
• 2016

Previous HI survey data have shown that the central HI gas in the Milky Way that resides within ~1.5 kpc of the Galactic Centre (GC) is tilted by ${\sim}15^{\circ}$ with respect to the Galactic plane. Although several models, such as a tilted disk model, have been suggested to interpret the observed morphology of the HI layer, it is still unknown what causes and how it preserves its tilted structure. We study the behavior of a gas disk near the GC using an N-body / SPH code. Our galaxy model includes four components; nuclear bulge, bulge, disk and halo. We construct a HI model whose radius is 1.3 kpc, scale height is 100 pc and mass is $3.6{\times}10^6M_{\odot}$. We also assume that the gas disk is initially tilted $30^{\circ}$ with respect to the Galactic plane. Here we report our simulation results and discuss the evolution of the tilted gas disk.

• 한국방송∙미디어공학회:학술대회논문집
• /
• 한국방송공학회 2002년도 정기총회 및 학술대회
• /
• pp.303-306
• /
• 2002

본 논문에서는 ATM(Asynchronous Transfer Mode) 기반의 Ka 대역 초고속 위성 TDMA(Time Division Multiple Access) 지구국 시스템인 HiSTARS (High-Speed Satellite TDMA Ground System )시스템에서 망 전체의 형상 및 자원 정보를 관리하며, 장애상태 및 사용 채널에 대한 과금 정보를 관리하며, 장애와 망 전체에서의 망 운용성능과 관련된 통계 정보를 운용자에게 알려주는 망운용관리시스템(Network Management System)을 소개한다. NMS는 운용자의 요구사항을 HiSTARS 시스템의 기준지구국에 위치한 중앙처리시스템과의 빠르고, 정확한 메시지 통신을 통해 즉각적으로 처리하며, 모듈별로 독립적으로 기능들이 구현되어 있으며. 이들 모듈간의 원활한 통신 및 데이터베이스를 통한 데이터 관리를 통해 HiSTARS 시스템의 망 전체를 효과적으로 관리하고 운용할 수 있도록 한다. 본 논문에서는 이러한 NMS의 디자인 및 구현 방법을 구체적으로 보이겠다.

• 대한설비공학회:학술대회논문집
• /
• 대한설비공학회 2007년도 하계학술발표대회 논문집
• /
• pp.213-213
• /
• 2007

• Corrosion Science and Technology
• /
• 제4권1호
• /
• pp.33-38
• /
• 2005

Some feasibility studies are conducted to produce an advanced ceramic coating, which reveals superior chemical and mechanical strength, on metal base structure used in chemical plant. This advanced coating on metallic frame can replace ceramic delivery pipe and reaction chamber used in chemical plant, which are operated in hi-temperature and corrosive/erosive environment. An dual spraying is adopted to reduce the residual stress in order to increase the coating thickness and the residual stress is estimated by in-situ manner. Then new methodology is tried to form special coating of yttrium aluminum garnet(YAG), which reveals hi-strength and low-creep rates at hi-temperature, superior anti-corrosion property, hi-stability against Alkali-Vapor corrosion, and so on, on iron base structure. To verify the formation of YAG during thermal spraying, XRD(X ray diffraction) technique was used.

• International Journal of Contents
• /
• 제5권3호
• /
• pp.98-106
• /
• 2009

For the success of a festival, effective volunteer management is axiomatic. Given the dramatically increased size and quality of festivals and events in Korea over the past fifteen years, the importance of effective volunteer management has been overlooked among festival organizations in comparison to similar festivals in western countries. This paper provides a description and an assessment of the Hi Seoul Festival 2009 volunteer program based on an seven-step ideal process of an effective festival volunteer program with suggestions for the program development by reviewing organizational documents, and an interview with a staff member of the Hi Seoul Festival organization, and a survey pertinent to festival volunteers' motivation. This study shows college students are more interested in volunteering at festivals in Korea with the primary motivation of developing relationships and gaining work experience. It also suggests that the Hi Seoul Festival organization should fully appreciate the importance of an effective volunteer program and the position and work of a volunteer coordinator.

• 천문학회지
• /
• 제37권2호
• /
• pp.61-77
• /
• 2004

We have searched for HI 21 cm line emission from shocked atomic gas associated with southern supernova remnants (SNRs) using data from the Southern Galactic Plane Survey. Among the 97 sources studied, we have detected 10 SNRs with high-velocity HI emission confined to the SNR. The large velocity and the spatial confinement suggest that the emission is likely from the gas accelerated by the SN blast wave. We also detected 22 SNRs which show HI emission significantly brighter than the surrounding regions over a wide ($>10 km\;s^{-1}$) velocity interval. The association with these SNRs is less certain. We present the parameters and maps of the excess emission in these SNRs. We discuss in some detail the ten individual SNRs with associated high-velocity HI emission.