• Title/Summary/Keyword: Secondary Sources

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Composition Variation of Atmospheric Fine Particulate Matters in Accordance with Air Mass Transport Pathways at Background Site of Korea in 2013 (국내 배경지역 대기 미세먼지의 기류 이동경로별 조성변화: 2013년 측정)

  • Ko, Hee-Jung;Lim, Eunha;Song, Jung-Min;Kim, Won-Hyung;Kang, Chang-Hee;Lee, Haeyoung;Lee, Chulkyu
    • Journal of Korean Society for Atmospheric Environment
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    • v.31 no.1
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    • pp.15-27
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    • 2015
  • The collection of fine particulate matter samples was made at Gosan site of Jeju Island, one of the background sites of Korea, during a year of 2013, and their water-soluble ionic species were analyzed in order to examine the chemical compositions and pollution characteristics. The concentrations of $nss-SO_4{^{2-}}$, $NH_4{^{+}}$, $NO_3{^{-}}$, and $K^+$ had occupied 66.0% of water-soluble ionic species in $PM_{10}$, especially 94.3% in $PM_{2.5}$ fine mode, however the $nss-Ca^{2+}$ and $Na^+$ showed high concentrations in $PM_{10-2.5}$ coarse mode. $NO_3{^-}/nss-SO_4{^{2-}}$ concentration ratios in $PM_{10}$ and $PM_{10-2.5}$ were 0.30 and 0.13, showing less significant effect from automobile and local pollution sources. The sulfate and nitrate compounds were presumed to be long-range transported to Gosan area by the relatively high SOR and NOR values. The trajectory cluster analysis showed the higher concentrations of the major secondary pollutants ($nss-SO_4{^{2-}}$, $NO_3{^{-}}$, $NH_4{^{+}}$) and $nss-Ca^{2+}$ when the air masses had moved from China continent and Korean peninsula into Gosan area.

The Study on the Enzyme Activities in Korean Bee Honey (한국산 벌꿀의 효소활성에 관한 연구)

  • 김성자
    • Journal of Environmental Health Sciences
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    • v.4 no.1
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    • pp.47-50
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    • 1977
  • This report is intended to describe as brief as possible the result of study on purity of the Korean Bee Honey. Purity of bee honey was measured by scaling the enzyme activities of two different honey groups: such as, the standard group and control group each including the samples of honey originated from the resource of acarcia, chestnut or miscellaneous origin. The samples of honey were collected from different sources: to wit, honey belonging to the standard group were collected from the township of Seoboo, Yangju county, Kyunggido province, Korea, while honey belonging to the control group were collected from the street side shops, market or the companies producing the secondary food from honey. The results of this study were summarized as follow: 1. It was found that honey belonging to the standard group contained less moisture than those belonging to the control group. Republic of Korea Ministry of Health and Social Affairs Food Control Regulation stipulates that honey must contain moisture less than 20%. The samples of' both groups contained moisture more than 20%, although honey belonging to the control group were relatively more so than honey belonging to the standard group. 2. Honey belonging to the standard group were found stronger in sugar reduction activities than those belonging to the control group. It was also noted that honey of acracia origin was strongest in reduction activities of the three different origin in the same group. 3. $\alpha$-Amylase and $\beta$-amylase were discovered to have activated more strongly in honey belonging to the standard group than those belonging to the control group. The enzyme activitie, varied depending on the origin of plant where honey comes from. For instance, honey of miscellaneous origin indicated the strongest activities in $\alpha$-amylase while honey of chestnut origirt indicated strongest in $\beta$-amylase.

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Design of Micro-structured Small Scale Energy Harvesting System for Pervasive Computing Applications (편재형 컴퓨팅을 위한 미세구조 에너지 하베스팅 시스템의 구조 설계)

  • Min, Chul-Hong;Kim, Tae-Seon
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.22 no.11
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    • pp.918-924
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    • 2009
  • In this paper, we designed micro-structured electromagnetic transducers for energy harvesting and verified the performance of proposed transducers using finite element analysis software, COMSOL Multiphysics. To achieve higher energy transduce efficiency, around the magnetic core material, three-dimensional micro-coil structures with high number of turns are fabricated using semiconductor fabrication process technologies. To find relations between device size and energy transduce efficiency, generated electrical power values of seven different sizes of transducers ($3{\times}3\;mm^2$, $6{\times}6\;mm^2$, $9{\times}9\;mm^2$, $12{\times}12\;mm^2$, $15{\times}15\;mm^2$, $18{\times}18\;mm^2$, and $21{\times}21\;mm^2$) are analyzed on various magnetic flux density environment ranging from 0.84 T to 1.54 T and it showed that size of $15{\times}15\;mm^2$ device can generate $991.5\;{\mu}W$ at the 8 Hz of environmental kinetic energy. Compare to other electromagnetic energy harvesters, proposed system showed competitive performance in terms of power generation, operation bandwidth and size. Since proposed system can generate electric power at very low frequency of kinetic energy from typical life environment including walking and body movement, it is expected that proposed system can be effectively applied to various pervasive computing applications including power source of embodied medical equipment, power source of RFID sensors and etc. as an secondary power sources.

Hierarchical Control Scheme for Three-Port Multidirectional DC-DC Converters in Bipolar DC Microgrids

  • Ahmadi, Taha;Hamzeh, Mohsen;Rokrok, Esmaeel
    • Journal of Power Electronics
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    • v.18 no.5
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    • pp.1595-1607
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    • 2018
  • In this paper, a hierarchical control strategy is introduced to control a new three-port multidirectional DC-DC converter for integrating an energy storage system (ESS) to a bipolar DC microgrid (BPDCMG). The proposed converter provides a voltage-balancing function for the BPDCMG and adjusts the states of charge (SoC) of the ESS. Previous studies tend to balance the voltage of the BPDCMG buses with active sources or by transferring power from one bus to another. Furthermore, the batteries available in BPDCMGs were charged equally by both buses. However, this power sharing method does not guarantee efficient operation of the whole system. In order to achieve a higher efficiency and lower energy losses, a triple-layer hierarchical control strategy, including a primary droop controller, a secondary voltage restoration controller and a tertiary optimization controller are proposed. Thanks to the multi-functional operation of the proposed converter, its conversion stages are reduced. Furthermore, the efficiency and weight of the system are both improved. Therefore, this converter has a significant capability to be used in portable BPDCMGs such as electric DC ships. The converter modes are analyzed and small-signal models of the converter are extracted. Comprehensive simulation studies are carried out and a BPDCMG laboratory setup is implemented in order to validate the effectiveness of the proposed converter and its hierarchical control strategy. Simulation and experimental results show that using the proposed converter mitigates voltage imbalances. As a result, the system efficiency is improved by using the hierarchical optimal power flow control.

Hydrogeochemical Evaluation of Crystalline bedrock Grondwater in a Coastal Area using Principal Component Analysis (주성분 분석을 이용한 해안지역 결정질 기반암 지하수의 수리지구화학적 평가)

  • Lee, Jeong-Hwan;Yoon, Jeong Hyoun;Cheong, Jae-Yeol;Jung, Haeryong;Kim, Soo-Gin
    • Journal of Soil and Groundwater Environment
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    • v.22 no.3
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    • pp.10-17
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    • 2017
  • In this study, the evolution and origin of major dissolved constituents of crystalline bedrock groundwater in a coastal area were evaluated using multivariate statistical and groundwater quality analyses. The groundwater types mostly belonged to the $Na(Ca)-HCO_3$ and $Ca-HCO_3$ types, indicating the effect of cation exchange. Stable isotopes of water showed two areas divided by first and secondary evaporative effects, indicating a pattern of rapid hydrological cycling. Saturation indices of minerals showed undersaturation states. Thus, the degree of evolution of groundwater is suggested as in the low to intermediate stage, based on field and laboratory analytical conditions. According to the principal component analysis (PCA) results, the chemical components of EC, $Ca^{2+}$, $Mg^{2+}$, $K^+$, $HCO_3{^-}$, $SO{_4}^{2-}$ (PCA 1), $F^-$ (PCA 3), $SiO_2$ (PCA 4), and $Fe^{2+}$ (PCA 5) are derived from various water-rock interactions. However, $NO_3{^-}$, $Na^+$, and $Cl^-$ (PCA 2) represented the chemical characteristics of both anthropogenic sources and natural sea spray.

Genetic and Pathogenic Characterization of Bacterial Wilt Pathogen, Ralstonia pseudosolanacearum (Ralstonia solanacearum Phylotype I), on Roses in Korea

  • Lee, Ingyeong;Kim, Yeong Son;Kim, Jin-Won;Park, Duck Hwan
    • The Plant Pathology Journal
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    • v.36 no.5
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    • pp.440-449
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    • 2020
  • The purpose of this study was to analyze the genetic and pathogenic characteristics of Ralstonia pseudosolanacearum in roses in Korea, and to examine the similarities and differences between Korean isolates and the first-reported European strains. Between 2017 and 2019, seventeen isolates from rose plants were identified as R. pseudosolanacearum using Ralstonia-specific primers. All 17 isolates were identified as race 1 using race-specific primers, and were confirmed as biovar 3 due to their ability to utilize carbon sources. Multiplex PCR using phylotype discriminating specific primers identified the 17 isolates as phylotype I. Sequevar comparison with reference sequevars using the sequences of the egl, mutS, and fliC genes, and only the egl gene, revealed that the strains evaluated in this study corresponded to sequevar I-33. The pathogenicity in roses differed depending on the rose cultivars. The different methods used for the genetic characterization of R. pseudosolanacearum indicate that the 17 rose bacterial wilt isolates had the same genetic characteristics. The lack of genetic variation in these isolates indicates their recent introduction from other countries (likely European countries). Therefore, appropriate quarantine and control measures should be taken in order to avoid further increases in the pathogenicity and/or secondary host range of R. pseudosolanacearum through genetic mutation.

Determination of the work function of the Ni thin films by using $\gamma-FIB$ system ($\gamma-FIB$ 장치를 사용한 Ni 박막의 일함수 결정)

  • 오현주;현정우;이지훈;임재용;추동철;최은하;김태환;강승언
    • Journal of the Korean Vacuum Society
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    • v.12 no.1
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    • pp.16-19
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    • 2003
  • Ni thin films on the p-InP (In) substrates were grown at room temperature by using the ion beam-assisted deposition. In order to determine the work function of the Ni thin films, the $\gamma$values were measured as functions of the acceleration voltages by using Ne, Ar, $N_2$. and Xe ion sources. The dependences of the values on various gases and on the acceleration voltages of the focused ion beam were obtained to determine the work function of the Ni thin films. The value of the work function of the Ni thin films grown on the p-InP (100) substrate was 5.8 eV ~ 5.85 eV. These results provide important information on the electronic properties of Ni thin films grown on p-InP (100) substrates at room temperature.

Geochemical Dispersion and Enrichment of Fluvial Sediments Depending on the Particla Size Distribution (입도분포에 따른 하상퇴적물의 지구화학적 분산 및 부화)

  • 이현구
    • Economic and Environmental Geology
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    • v.32 no.3
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    • pp.247-260
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    • 1999
  • Geochermical characteristics of the fluvial sediments deprnding on particle size distribution size were investigated in the respect of majir, minor and rare eath element chemisitry. Ratios of $Al_{2}O_{3}/Na_{2}O$ and $K_{2}O/Na_{2}O$ of the sediments show the homogeneous valus, and partly positive correlation with $SiO_{2}/Al_{2}O_{3}$, respecively. Characteristics of minor element ratios (V/Ni, Cr/V, Ni/Co and Zr/Hf)are within the lower and narrow range. Thesesuggested that sediment sources may be acidic to intermediate granitic rock, and may be explained by simple weathering and sedimentation. With increasing SiO2 contents, concentrations of $Al_{2}O_{3}$, $Fe_{2}O_{3}$, CaO and MgO decreased, but those of $K_{2}O$ and $Na_{2}O$ increased, Concentrations of Ba, Be, Cs, Cu, Li, Ni, Sr, V and Zr show comparatively normal negative and some positive trends. Compared with the mean composition of granite, concentrations of $Al_{2}O_{3}$, $Fe_{2}O_{3}$, MnO, CaO and MgO in the sediments of the study area were highly enriced. Among some minor and rare earth elements, concentrations of As, Cd, Cu, and V were enriched, but those of Be, Ce, Rb, Sc, Sr and Zn were depleted when compared with average composition of granite. By decreasing of particle size fractions, SiO2, Rb and Sr conterts decreased, but concentrations of $Al_{2}O_{3}$, $Fe_{2}O_{3}$, CaO, MgO, $TiO_{2}$, MgO, $P_{2}O_{5}$, Be, Cu, Hf, Pb, V and Zr increased. From the correlations between particle size fractions and element concenreations, some elements of $Fe_{2}O_{3}$, CaO, MgO, $P_{2}O_{5}$, Cu, Ni, Zn and Zr showed typical trends in the secondary contramination sediments. These trends are typically shown under 100 mesh fractions. It indicates that the fraction of minus 100 mesh is the optimum size fraction for geochemical and environmental survey.

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GIS Technology for Environmental Gelolgic Mapping (환경 지질도 작성을 위한 GIS 응용연구)

  • 김윤종;유일현;김원영;신은선
    • The Journal of Engineering Geology
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    • v.4 no.3
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    • pp.321-331
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    • 1994
  • Environmental geologic maps were produced on the cheong-Ju area using GIS technique. They are GIS maps on land management and regional land use planning. In the last year, the model of environmental geologic map was established, and the digital database was constructed by environmental and geotechnical data collected form various sources. The special maps for environmental geologic study were also pnoduced ; landslide hazard and risk map, cut & fill map, actual run-off map and engineering geological map. The maps are secondary models (sub-model) in order to create final environmental geologic map. Finally, Environmental Geologic Unit(EGU) was evaluated for regional land use planning and land management by EGIS(Environmental Geologic Inforafion System). This unit is very important in order to assess environmental geologic impact on large construction works and detailed road design etc.

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The Relationships between Health Behaviors, Mental Health and Smoking among Korean Adolescents (한국 청소년의 건강행태 및 정신건강과 흡연의 관련성)

  • Song, Hye-Young;Doo, Eun Young;Choi, Sujin
    • The Journal of the Korea Contents Association
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    • v.17 no.7
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    • pp.557-570
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    • 2017
  • This study, as a secondary analysis research, bases its source upon on raw data from the on-line survey of the Korean adolescents' health behaviors in 2015. This study was conducted to clarify the relevance of Korean adolescents' smoking with their health behaviors and mental health, and thus further to provide basic sources of effective education for their smoking prevention and for program development. The results of the study showed that Korean adolescents' smoking was significantly affected by the adolescents' sex, grades, school achievements, types of schools, allowances, economic status, parents' educational background (p<0.001). Meanwhile, smoking based on the characteristics of health behaviors was significantly different according to alcohol consuming experience, families' and friends' smoking, physical activity and subjective health status, and BMI (p<0.001). Smoking characterized by mental health showed the significant difference in their stress recognition, subjective sleep patterns, depressed experiences, suicidal ideation, and subjective sense of happiness (p<0.001). Based on all the factors regarding youth smoking, there should be development and provision of educational program for smoking prevention and cessation, including healthy behavior and mental health improvement for Korean adolescent.