검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 239

        221.
        2006.07 KCI 등재 서비스 종료(열람 제한)
        Based on the monthly weather report of Korea Meteorological Administration (KMA) and daily sea surface temperature (SST) data from National Fisheries Research and Development Institute (NFRDI) (1995-2004), mean heat fluxes were estimated at the port of Yeosu. Net heat flux was transported from the air to the sea surface during February to September, and it amounts to 205 Wm-2 in daily average value in May. During October to January, the transfer of net heat flux was conversed from the sea surface to the air with -70 Wm-2 in minimum of daily average value in December. Short wave radiation was ranged from 167 Wm-2 in December to 300 Wm-2 in April. Long wave radiation (Sensible heat) was ranged from 27 (-14) Wm-2 in July to 90 (79) Wm-2 in December. Latent heat showed 42 Wm-2 with its minimum in July and 104 Wm-2 with its maximum in October in daily average value.
        222.
        2006.06 KCI 등재 서비스 종료(열람 제한)
        이 연구의 최종목적은 기존의 선박용 자기 컴퍼스를 대체할 수 있는 디지털 컴퍼스 개발에 있다. 우선, 3축의 고정밀 프럭스-게이트센서와 소형 스텝 모터를 이용하여 새로운 디지털 컴퍼스 장치를 개발하였다. 그리고 기존 자차측정 방법과 달리 선박의 선회 없이 자동으로 자차의 분석과 수정이 가능하도록 기존 자차이론에 칼만필터 개념을 접목시킨 새로운 자차수정 이론을 제안하였다. 개발한 디지털 컴퍼스와 제안한 자차수정 방법의 유효성을 실습선 '새누리호'를 이용한 성능평가 실험을 통하여 유효성을 검증하였다.
        223.
        2006.02 KCI 등재 서비스 종료(열람 제한)
        Atmospheric bulk (wet and dry) samples were monthly collected in Masan and Heangam areas of Korea, to assess the deposition flux and seasonal variation of polycyclic aromatic hydrocarbons (PAHs). Deposition fluxes of PAHs in bulk samples were determined using gas chromatography coupled to mass spectrometer detector (GC/MSD). Particle deposition fluxes from Masan and Haengam areas varied from 13 to 87 g/m2/year and from 5 to 52 g/m2/year, respectively. PAHs deposition fluxes in atmospheric bulk samples in Masan and Haengam areas ranged from 135 to 464 µg/m2/year and from 62.2 to 194 µg/m2/year, respectively. Atmospheric deposition fluxes of particles and PAHs in this study were comparable to or slightly lower values than those from different locations in Korea and other countries. PAHs profiles of atmospheric deposition bulk samples showed slightly different from two sampling areas, however the predominant species of PAHs were similar. Indeno (1,2,3-c,d)pyrene, benzo(g,h,i)perylene, phenanthrene compounds were the most detected PAHs in deposition bulk samples. Carcinogenic PAHs occupied the contribution of approximately 30-40% of the total PAHs deposition fluxes. The non-metric multi-dimensional scaling (MDS) was used, to assess the differentiation of PAHs source between two sampling areas. The result suggests that PAHs contamination sources were different according to the location and season surveyed. There was no an apparent relationship between the PAHs deposition flux against temperature and rainfall amount, even though summer season with the highest temperature and the largest amount of precipitation showed the lowest PAHs deposition flux. Benzo(e)pyrene/benzo(a)pyrene ratio indicated that the photo-degradation process was one of important factors to the seasonal variation of PAHs with the lower deposition fluxes.
        225.
        2004.05 KCI 등재 서비스 종료(열람 제한)
        Atmospheric bulk (wet and dry) samples were monthly collected in an urban environment (Daeyeon-dong) of Busan over a year, to assess the deposition flux and seasonality of dioxin-like polychlorinated biphenyls (DLPCBs) using stainless steel pots. Deposition fluxes of DLPCBs in bulk samples were determined using high resolution gas chromatography coupled to high resolution mass spectrometry (HRGC/HRMS). Particle deposition fluxes in the urban environment varied from 23 to 98 g/m2/year (mean 41 g/m2/year). DLPCB deposition fluxes in atmospheric bulk samples ranged from 0.09 to 0.77 ng-TEQ/m2/year (mean 0.35 ng-TEQ/m2/year). Seasonal atmospheric deposition fluxes of DLPCBs were high in winter and low in summer. Atmospheric deposition fluxes of particles and DLPCBs in this study were comparable to or slightly lower values than those of different locations in the world. Monthly DLPCB profiles in deposition bulk samples were similar over a year. Non-ortho PCBs were higher contributions to the total DLPCBs fluxes than mono-ortho PCBs. In particular, PCB 126 had the highest concentrartion (>75%) in all deposition samples, followed by PCB 169 and PCB 156. A highly positive correlation was found among the deposition fluxes of DLPCB species, suggesting the possibility of that the DLPCB contamination originated from one source. The deposition fluxes of DLPCBs were not significantly correlated with temperature and the amount of precipitation even though the summer season with the highest temperature and the largest amount of precipitation showed the lowest DLPCB deposition flux.
        226.
        2003.10 KCI 등재 서비스 종료(열람 제한)
        본 연구에서는 비구조격자 좌표계상에서 천수방정식 해석을 위한 수치모형을 개발하였다. Fractional step method를 이용하여 이차원의 천수방정식을 두개의 일차원 문제로 분리하여 계산 효율이 우수한 수치연산을 수행하였다. 분리된 일차원 문제는 이차정확도의 TVD 기법을 이용하여 해석하였다. TVD 기법은 HLLC 기법을 이용하여 Riemann 해를 구한후 WAF 기법을 기반으로 이용하였으며 WAF 흐름율 제한자를 이용하여 이차정확도 문제에 수반
        227.
        2002.12 KCI 등재 서비스 종료(열람 제한)
        The purpose of this study is to estimate wet deposition flux and to investigate wet deposition characteristics by using the ADOM model. Wet deposition flux of highly reactive SO2 is estimated by applying observed meteorological parameters and concentrations of chemical species to the ADOM model. Wet deposition is largely dependent on large scale precipitation and cloud thickness. Wet deposition flux of sulfate depends on SO2 oxidation in clouds. When large amount of SO2 is converted to sulfate, deposition flux of sulfate increases, but wet deposition flux of SO2 is small. On the whole, the pattern of sulfate wet deposition flux agrees with the typical pattern of sulfate wet deposition that is high in the summer(July) and low in the winter(January).
        228.
        2002.12 KCI 등재 서비스 종료(열람 제한)
        2-체널 링-코어 프럭스-게이트 콤파스(Two-Channel Ring-Core Flux-Gate Compass; TCRC FG-Compass)의 성능평가 시스템 설계와 구현방법 및, 다항회귀 모형 기반의 평가 절차와 방법을 기술했다. 성능평가 시스템은 스템모터 구동 유닛과, 방위정보 전송 유닛, 다항회귀식에 의한 평가 프로그램 등으로 구성하였다. 성능평가 실험결과, TCRC FG-Compass는 잔차가 2˚인 반면, 기존의 FG-Compass는 잔차가 4˚임을 나타냈다. 따라서 성능이 향상된 새로운 FG-Compass 설계가 가능함을 확인하였다. 또한, 자동으로 잔차를 추정하고 보정할 수 있는 설계론에 관해서도 논의하였다.
        229.
        2002.07 KCI 등재 서비스 종료(열람 제한)
        Weather elements were observed by the AWS (Automatic Weather System) and dustfall particles were collected by the modified American dust jar (wide inlet bottle type) at 4 sampling sites in Busan area from March, 1999 to February, 2000. Thirteen chemical species (Al, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Ni, Pb, Si, and Zn) were analyzed by AAS and ICP. The purposes of this study were to estimate qualitatively various bulk deposition flux of dustfall and insoluble components by applying regional and seasonal wind intensity. Frequency of wind speed were found in order of low(1-3㎧), very low(<1㎧), medium(3-8㎧) and high(>8㎧), and annual mean had higher range at low(1-3㎧) for 56.3%. Strong negative linear correlation were observed between dustfall and wind direction (northeastern and eastern), but strong positive linear correlation were observed between dustfall and wind direction (western and northwestern) at industrial, commercial and coastal zone(p<0.05). While a negative correlation were observed between wind speed frequency of very low(<1㎧) and dustfall, and positive correlation were observed between wind speed frequency of low(1-3㎧) and dustfall in coastal zone(p<0.05). The correlation coefficient was observed 0.556 between wind speed frequency of low(1-3㎧) and Ni by commercial zone(p<0.05). The correlation coefficient show well-defined insoluble trace metals (Al, Ca, Cr, Cu, Fe, Pb, and Zn) and wind speed frequency of low(1-3㎧) at coastal zone, which was found significant difference(p<0.01).
        230.
        2002.03 KCI 등재 서비스 종료(열람 제한)
        항공 대잠수함전에 사용되는 방향주파수분석저장 소노부위 (DIFAR Sonobuoy)에 방위정보를 제공하는 플럭스-게이트 콤파스의 위상감응검출 (PSD) 회로 설계와 구현에 관해서 기술하였다. PSD 회로는 쌍동-T RC 회로망을 갖는 능동형 대역필터로 구성하였다. PSD 회로에 대한 성능실험 결과, 대역통과 필터가 지구자장 방향에 비례하는 2Fe의 2차 고조파 신호를 효과적으로 걸러냄을 확인하였다. 그 결과 방위 신호 정보를 획득할 수 있었다.
        231.
        2001.06 KCI 등재 서비스 종료(열람 제한)
        Dustfall particles were collected by the modified American dust jar (wide inlet bottle type) at 6 sampling sites in Pusan area from March, 1999 to February, 2000. Thirteen chemical species (Al, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Ni, Pb, Si, and Zn) were analyzed by AAS and ICP. The purposes of this study were to estimate qualitatively various bulk deposition flux of dustfall and insoluble components by applying regional and seasonal distribution. Dustfall amount of regional variations were found in order of coastal zone, industrial zone, commercial zone, agricultural zone and residential zone, and seasonal total dustfall had higher concentrations during spring for 6.741 ton/㎢/season, lower concentrations during summer for 1.989 ton/㎢/season, and annual total concentration was 17.742 ton/㎢/year. The regional distributions of enrichment factor show well-defined anthropogenic metals (Cd, Cu, Pb, and Zn) at industrial and agricultural zone, and contribution rate of soil particles were found in order of summer, fall, winter and spring. Factor loading effects of chemical composition of dustfall were found in order of road traffic emission source and combustion processed source, industrial activity source, soil source and marine source.
        232.
        2001.02 KCI 등재 서비스 종료(열람 제한)
        This study was carried out estimating the dry deposition flux of SO2 at eight urban areas in Korea during one year of 1996. To calculate the deposition flux, deposition velocities were calculated by turbulence parameters estimated from routine meteorological data. Also, hourly averaged SO2 concentrations which calculated from air pollution monitoring data of each city were used. The dry deposition velocities were mostly higher in the coastal areas than the other areas, which would be caused by relatively strong wind. And, they were high in the daytime because of turbulence activities. The deposition flux of SO2 is mainly related to the atmospheric concentration. The annual average SO2 concentration and the deposition flux were 22.62ppb and 1510.52g/㎢/hr at Pusan respectively. Also, the flux was higher in winter than other season, which was a significant contribution of exhausted fuel for heating. While the deposition velocity was high to 0.688㎝/sec at Yosu in case of strong wind and small cloud cover, the deposition flux was high to 1597.4g/㎢/hr at Pusan in case of weak wind and small cloud cover.
        233.
        2000.04 KCI 등재 서비스 종료(열람 제한)
        The purpose of the present study is to develope the estimation scheme for sensible heat flux by semi-empirical approach using routine meteorological data such as solar radiation and air temperature. To compare observed sensible heat flux with estimated sensible heat flux, the sensible heat fluxes were measured by three dimensional sonic anemometer-thermometer. The field observation was performed during 1 year from December 1, 1995 to November 30, 1996 on a rice paddy field in Chunchon basin. The heat fluxes were measured at a heights of 5m and mean meteorological variables were obtained at two levels, 2.5m(or 1.5m) and 10m. Since condition of rice paddy field such as, wetness of the field, roughness length, vary widely, we devided annual data to 5 periods. Comparing with two sensible heat fluxes, the results showed that the correlation coefficients were more than 0.86. Thus, we can conclude that the estimation method of sensible heat fluxes using routine meteorological data is practical and reliable enough.
        236.
        1998.10 KCI 등재 서비스 종료(열람 제한)
        The concentrations and wet deposition flux into the sea of heavy metals of precipitation in Pusan area were measured and estimated. The samples were collected by polyethylene bottle(30ℓ) from January to November in 1996, and heavy metals were analyzed by atomic absorption spectrometer. The concentration order of heavy metals was Al >Fe >Zn >Pb >Mn >Cu >Ni >Cd >Co, and they were high at inland sites and low at coastal sites. The enrichment factors for some metals(Zn, Cu, Pb, Cd), based on crustal Al, were significantly greater than unity, and the order was Cd > Pb > Zn > Cu. This evidence suggests Cd and Pb are derived predominantly from non-crustal sources. Al, Fe and Mn contents showed good correlation with each other. Therefore this enrichment factor indicates similar geochemical behavior of these elements. The annual wet depositional flux(㎎/㎡/yr) from P1 site was as follows: Al (121.1), Fe,(177.2), Zn(12.9), Mn(6.19), Pb(14.4), Cu(0.64), Ni(1.03), Cd(1.02) and Co(1.01).
        237.
        1998.10 KCI 등재 서비스 종료(열람 제한)
        A Jump model was evaluated for the calculation of hourly mixing height and mean potential temperature within the height. The Jump model was modified for estimation of downward heat fluxes by mechanical convections and surface heat fluxes. The surface heat fluxes were estimated from routine weather data such as solar radiation and air temperature. Total of 8 upper-air data observed at 0000UTC and 0600UTC in Osan station during April 23 to 26, 1996 were analyzed, and compared to the model results in detail. The calculated mixing heights and potential temperatures within the height were comparable to the observations, but some differences were showed. The calculated mixing heights were generally higher than observations. And, when variations of wind directions were large, the large difference of potential temperature was occurred. From the results, it was important to note that vertical motions and advections of air masses would affect to the growth of the mixing height.
        238.
        1997.12 KCI 등재 서비스 종료(열람 제한)
        In order to see the stratification related to the heat flux in Deukryang Bay, the oceanographic data on July 12, 1994 and the meteorological data of Kohung and Kwangju meteorological stations were analyzed. The temperature differences between the sea surface and the near bottom were 1∼3℃ on spring tide (July 12, 1994) in Deukryang Bay. The air temperature anomalies were high about 3℃ during summer in 1994. These mean that the tidal mixing was not effective in destroying the stratification due to the sea surface heating by the solar radition, even though it was on spring tide. The maximum solar radiation was about 600 ly/day, which was the value of the same date of oceanographic observation. The sensible and the latent heat flux which are 0∼100 ly/day were not so varied during summer. The absorbed heat flux through the sea surface was mostly lost by the back radiation, which ranges are about 0∼-400 ly/day. The dimensionless mixing parameter related to the buoyancy flux was 5∼-150×l0 ㄷ테 (-5). The efficiency of tidal mixing to destroy the stratification was 0.4∼0.6%.
        11 12