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        검색결과 41

        1.
        2016.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We investigate the long-term spatial drift of the center and the temporal variation of the shutter delay time map of Y4KCam mounted on the CTIO 1.0 m telescope. We have collected shutter delay time maps over eight years as a part of our long-term survey program. We find that the center of the shutter delay time map can drift up to 450 μm, equivalent to  30 pixels, on the CCD. This effect can result in a small amount of error in integration time without the proper shutter delay time correction, but it does not appear to cause any significant problems in photometric measurements. We obtain a mean shutter delay time of 69.1 ± 0.8 ms and find no temporal variation of the shutter delay time of Y4KCam over eight years, indicative of the mechanical stability of the shutter. We suggest that using a master shutter delay time correction frame would be sufficient to achieve high precision photometry, which does not exceed photometric errors ~ 1.7 mmag across the CCD frame for exposure times longer than 1 s.
        4,000원
        2.
        2016.11 구독 인증기관·개인회원 무료
        PVDF Membrane has been used as material for the UF membrane through in-situ interfacial polymerization (IP) because of it’s outstanding properties such as high chemical resistance, thermal stability, and mechanical strength. In this study, surface morphology change of PVDF membrane was researched depending on evaporation time. 13% PVDF 6020 was used for casting and the evaporation time period was from 5s to 600s. The surface morphology of the membrane was investigated by scanning electron microscopy (SEM) and filtration was conducted in the cross flow method to evaluate the a performance of UF membrane. As a result, average pore size was increased with longer evaporation times which caused the decrease of rejection.
        3.
        2016.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was an attempt to analyze the basic analytical characteristics of octanal and nonanal compounds by TD and GC/FID system. The basic analysis (linearity, precision, MDL: method detection limit) showed similar results for VOCs in terms of QA/QC results with the same analysis system. Also, the results are sufficiently satisfy the QA/QC of the Korean odor analysis standard method. When using a polyester aluminum bag, the amount of loss was found to be about -2% to 7%. Adjusting the relative humidity and loss trend with the passage of time, the loss amount is found to be only a trace amount. With the exception of the styrene compound, all volatile organic compounds have a tendency to decrease slightly. Similar results were shown from Octanal and Nonanal. As a result, Octanal and Nonanal compound’s adsorption amount by the polyester aluminum bag was a quite small. The relative humidity and other compounds appear to be significantly unaffected by Octanal and Nonanal.
        4,500원
        4.
        2013.03 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        This study investigated viability variation of airborne bacteria in indoor environments. The survival in air as a temporal function of bioaerosol viability was reported for Escherichia coli (KCCM 12119, ATCC 11775). Bacteria suspended in distilled water were aerosolized and entered the vertical duct oriented downward. After measurement of number concentration and colony forming unit (CFU) of the bacteria at different locations of the duct, the viability function was calculated. It was found that the bacteria viability(%) decreased with time after aerosolization, 28.454e-0.132x (x:time, min). This study demonstrated the potential application of viability function of airborne bacteria to studies of exposure assessment and infection risk analysis.
        4,000원
        5.
        2011.11 구독 인증기관 무료, 개인회원 유료
        본 연구는 낙동강 담수유입과 하구역내로 하구밀도류 및 바람장 특성에 따른 수괴 거동특성을 예측하고 하구역 해수순환구조를 파악 하기위해 3차원 실시간 해수유동 모형을 구축하고 2007년을 기존 자료를 입력하여 365일의 실시간 수치실험을 수행하였다. 계산결과와 현장조 사결과를 바탕으로 검증을 수행하였으며 바람이 있는조건과 없는 조건을 고려하여 수온과 염분의 경년변화를 살펴보았다.
        4,000원
        7.
        2007.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to investigate the effect of parity and region on the live body charateristics of Hanwoo cows. The data used were logissimus muscle area (LMAU), back fat thickness (BFTU), marbling score (MSU), and p8 point fat thickness (P8 FTU), by ultrasound from 1,239 heads of hi-lok branded Hanwoo cows. Based upon ultrasound characteristics of LMAU, BFTU, MSU and P8 FTU were significantly high in Hanwoo cows in Hwacheon area. Live body characteristics were increased with the parity, however estimated value tended to decreased after sixth parturition. Also, comparative of pre or after parturiti- on on the live body characteristics, pre parturition value showed little lower than after parturition
        4,000원
        8.
        2006.12 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        This study was carried out to evaluate the characteristics of volatile organic compounds (VOCs) and aldehydes emission as a function of airtight time in new apartment. Sampling was undertaken at 34 new apartments located in 4 different cities of Korea from February to November 2005. The measurement data were collected every one hour from 10 a.m. to 6 p.m. toward increasing airtight time in a day. The concentrations of VOCs and aldehydes were analysed by GC/MS and HPLC method, respectively. These methods showed good sensitivity, linearity, and repeatability. In this study, the most abundant compounds at new apartments appeared to be toluene, m,p-xylene, formaldehyde and acetone. Moreover, the concentration variations at a closed rooms progressively increased by airtight time of 5 hours. Airtight time of new apartment was a most important and affective factor which influenced concentration change.
        4,300원
        11.
        1997.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 논문에서는 랜덤한 축대칭 기하학적 초기결함을 갖는 원통이 축방향 충격하중을 받는 경우의 반경방향 변위가 임계기준치를 최초로 통과하는 확률론적 충격좌굴 파괴시간을 해석할 수 있는 방법을 제시하였다. 랜덤한 기하학적 초기결함의 생성을 위해 초기결함의 평균함수 및 상관함수를 이용하여 확률장을 형성하는 방법을 사용하였다. 본 논문에서 제시된 방법은 실제적인 기하학적 초기결함이 갖는 불확실성을 취급하는데 적절하고 실용적이므로 이를 고려한 원통의 구조안전도해석에 이용할 수 있다.
        4,200원
        12.
        1995.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The variation of the urban water demand and the amount of water in the distribution reservoir was studied with time for a day. The city of Kwangju in Korea was selected as a study area. The population of Kwangju in the end of 1993 was more than one million and two hundred thousand peoples. The average of daily water use in 1993 was about three hundred and fifty thousand tons a day. One day was devided into 12 divisions with a 2 hour increment. The water use demand related to the amount of water in the distribution reservoir was observed for the given time interval of a day. The water use index was defind in percentage that indicates the ratio of the amount of water use for a time interval to the amount of water use for a day. The water use index with consideration of the water stored in the reservoir was found to be useful to manage and to operate the water supply systems in real time.
        4,000원
        13.
        1994.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We have detected a SiO maser line (v=1, J=2- 1) for 15 stars out of about 80 long period variables in the wide range of period. No new sources are detected; all detected sources are variables with period longer than 300 days; no evidence is found that the dust grains in the outer envelope have influenced on this line. The time variation of this maser line for 7 stars, T Cep, μ Cep, U Her, R Leo, R Lmi, U Ori, and R Ser is observed and compared with optical light curve at the same epoch of maser observation. No universial relation between the time variation and the optical light curve is found. It implies that the radiation from a central star does not much play an important role for the direct pumping of the SiO maser line.
        4,600원
        15.
        1984.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 경상남도 진주에 위치한 농촌진흥원 해충 시험포장에서 Carbofuran 입제를 본답기에 2회 처리와 농가 관행방제인 살충제 9회 처리간의 벼 해충과 이들 천적의 밀도를 비교 조사하였다. 1. Carbofuran 입제를 기계이앙시 육묘상자 처리와 7월중순 수면 처리등 본답기에 2회만 처리하여도 벼의 주요해충인 멸구 매미충류, 나방류, 굴파리, 총채벌레등의 방제효과가 관행 방제인 살충제 9회 처리와 비등한 경향이었다. 2. 벼 해충의 천적인 거미류와 멸구류의 난기생봉(Anagrus sp.)의 밀도는 Carbofuran 입제 처리가 관행방제보다 2.4배 밀도가 높았다.
        3,000원
        16.
        2017.12 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        The electric coupling between the lithosphere and the ionosphere is examined. The electric field is considered as a timevarying irregular vertical Coulomb field presumably produced on the Earth’s surface before an earthquake within its epicentral zone by some micro-processes in the lithosphere. It is shown that the Fourier component of this electric field with a frequency of 500 Hz and a horizontal scale-size of 100 km produces in the nighttime ionosphere of high and middle latitudes a transverse electric field with a magnitude of ~20 mV/m if the peak value of the amplitude of this Fourier component is just 30 V/m. The time-varying vertical Coulomb field with a frequency of 500 Hz penetrates from the ground into the ionosphere by a factor of ~7×105 more efficient than a time independent vertical electrostatic field of the same scale size. The transverse electric field with amplitude of 20 mV/m will cause perturbations in the nighttime F region electron density through heating the F region plasma resulting in a reduction of the downward plasma flux from the protonosphere and an excitation of acoustic gravity waves.
        17.
        2017.12 KCI 등재 서비스 종료(열람 제한)
        It is important for radish to have late flowering characteristics especially in the case of spring and winter cultivars. To understand late flowering characteristics of radish at the molecular level the flowering time genes of two radish lines (NH-JS1 and NH-JS2) with different flowering time were compared by re-sequencing their genomes. There were a total of 872,587 SNPs and 194,637 INDELs between the two lines. The SNP density of each chromosome was relatively uniform throughout, but the region with low SNP density was found at the end of R3 and the middle of R9. To compare the flowering time genes of the two lines, we first looked for the flowering time genes in radish using Arabidopsis thaliana flowering time genes. As a result, homologs of radish were found for most flowering time genes, but FRIGIDA was not found. Among 224 radish flowering time gene-homologs found, 97 genes showed more than one sequence difference (SNP or INDEL) between the two lines, and 127 genes had no difference. In particular, no sequence differences were found in FT, CO, and FLC, core flowering time control genes. Rs350520 (FVE), Rs193800 (CURLY LEAF) and Rs255320 (ATX1) with more than 100 sequence variations were expected to have a significant effect on flowering time difference between the two lines. These results will be of great help in understanding the flowering timing difference between the two lines at the molecular level.
        18.
        2014.07 서비스 종료(열람 제한)
        In rice (Oryza sativa L.), there is a diversity in flowering time that is strictly genetically regulated. The floral transition from vegetative to reproductive development is a very important step in the life cycle of a flowering plant. Although the genetic pathway for short-day flowering in rice is relatively well understood, the naturally occurring molecular mechanisms underlying flowering time diversity of the cultivated rice are still not clear. Resequencing of 295 rice accessions including 137 HS and 158 KB rice accessions, was recently finished with an average of approximately 10x depth and > 90% coverage. A wide range of variation in flowering time was observed within a diversity research set of 295 accessions ranging from 28 to 72 days. GWAS was performed using the resequencing data to investigate the candidate genes associated with flowering time in rice. Our GWAS result suggests that two SNPs in the promoter or 3’ UTR of the ‘Arabidopsis CO’ homolog FBH1 are potentially associated with early flowering. The new SNPs found in the FBH1 locus would be useful in developing markers to screen the varieties with early flowering time in the future molecular breeding.
        19.
        2014.03 KCI 등재 서비스 종료(열람 제한)
        본 연구는 남부지역에서 주요 콩 품종의 파종기 이동이 isoflavone 등 생리활성물질에 미치는 영향을 구명하고자 전남 나주(위도 35° 04'N, 경도 126° 54'E)에서 2008년부터 2010년까지 3년간 수행되었다. 여름형콩 품종인 새올콩과 다원콩, 가을형콩 품종인 태광콩, 풍산나물콩 및 청자3호를 이용하여 파종기를 5월 15일, 5월 30일, 6월 15일, 6월 30일, 7월 15일에 실시하였으며, 주요 결과를 요약하면 다음과 같다. 1. Daidzein 함량은 모든 시험품종에서 genistein과 total isoflavone 함량은 청자3호를 제외한 시험품종에서 파종이 늦어질수록 증가하는 경향이었다. 반면에 glycitein 함량은 다원콩을 제외한 시험품종에서 파종기간 유의차가 없었다. 2. Cyanidin-3-glucoside(C3G) 함량은 다원콩과 청자3호, delphinidin-3-glucoside(D3G)와 total anthocyanin 함량은 다원콩에서만 파종이 늦어질수록 유의하게 증가하였다. 그러나 pelargonidin-3-glucoside(Pg3G)와 petunidin-3-glucoside(Pt3G) 함량은 파종기간 유의차가 없었다. 3. 청자3호의 lutein 함량은 파종기에 따라 2.7~3.0 μg/g로 유의차가 없었고, chlorophyll 함량은 파종이 늦어짐에 따라 증가하여 6월 30일과 7월 15일 파종에서 유의하게 많았다. 4. 조지방 함량은 태광콩과 청자3호는 조기에 파종할 때 많았고 기타 시험품종은 파종기간 유의차가 없었다. Palmitic acid 조성비는 대부분 시험품종에서 파종기의 영향을 받지 않았다. Stearic acid 조성비는 새올콩, 다원콩, 청자3호에서 파종이 늦을수록 증가하였다. Oleic acid, linoleic acid 조성비는 새올콩에서만 파종기가 빠를수록 유의하게 높았다. Linolenic acid 조성비는 대부분 시험품종에서는 파종이 늦을수록 유의하게 증가하였다. 5. 파종기 이동에 따른 탄수화물과 조단백질 함량은 대부분 시험품종에서 유의차가 없었다. 그러나 새올콩은 조기에 파종할수록, 다원콩은 만기에 파종할수록 조단백질 함량이 많은 경향이었다.
        20.
        2014.02 서비스 종료(열람 제한)
        열적외선 위성영상은 저비용으로 안전하게 지표온도를 추정할 수 있으며, 따라서 열적외선 위성영상을 활용하는 것으로 화산활동의 전조현상 모니터링이 가능하다. 그러나, 지표온도를 추정하기 위해 필요한 요소인 지표의 복사율 결정과 대기효과 보정은 쉽지 않기 때문에, 높은 정밀도를 기대하기 어렵다는 단점이 존재해왔다. 이에 본 연구에서는 최근 개발된 LSTD(Land Surface Temperature Difference)기법을 활용하여, 높은 정밀도의 지표온도 추정방법을 제안하고자 한다. 이 방법은 임의의 기준점으로부터 상대적인 지표온도의 차이를 구하는 것으로 대기효과를 보정하며, 복사율이 잘 알려진 식생지역에 한정적으로 적용함으로써 0.5K 이하의 높은 정밀도의 지표온도 추정이 가능한 것으로 알려져있다. 이 방법은 1) 대기효과 보정, 2) 식생지역의 추출, 3) 기준점의 지표온도로부터 상대적인 지표온도차 계산 및 4) 온도감률로부터 지형효과 보정의 단계로 이루어진다. 제안된 방법의 실험을 위하여, 화산활동이 활발한 아프리카의 Nyiragongo화산과 최근 전조현상이 발생하고 있는 백두산을 연구지역으로 선정하였으며, 열적외선 밴드를 탑재한 Landsat TM/ETM+ 영상을 수집하였다. 제안된 방법은 식생지역에만 적용되는 것으로서 공간적인 한계가 있으나, 높은 정밀도로 지표온도의 추정이 가능하기 때문에 화산활동의 전조현상을 관측할 수 있을 것으로 기대된다.
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