• 한국산업보건학회지
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• 제18권2호
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• pp.99-107
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• 2008

We quantified the human carcinogenic metals (chromium, nickel) in fumes from flux cored arc welding using stainless steel (FCAW/SS) wires. Zinc and calcium were also quantified because of their possibility of zinc chromate and calcium chromate, respectively. Welding was performed in an American Welding Society standard fume collection chamber. Insoluble and soluble forms of metals were analyzed by ISO 15202 method. Total chromium (insoluble+soluble) content and total nickel content were lower in FCAW/SS fumes (4.65%, 1.05%, respectively)than in stainless steel content (ca. 18%, 8%,respectively). Insoluble fraction in total chromium was 79.8 (range 64.5~95.1)% and 94.4(range 90.1~98.1)% in total nickel. Atomic emission spectroscopy used in this study does not differentiate the chromium valence status while ACGIH defines its carcinogenicity according to the valence status. From this study and previous study, we estimated the hexavalent chromium content in FCAW/SS was 0.2~1.1% and about 85% of them was soluble. The content of zinc and calcium, which can be existed as chromate forms, was low (0.02 %, 0.04% respectively) in FCAW/SS. Exposure assessment for zinc chromate and calcium chromate is possible because chromium in both compounds is used as a surrogate even though it is not well known that what compounds of zinc and calcium are formed in welding fume.

• ALGAE
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• 제36권4호
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• pp.315-326
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• 2021

Ion channels are membrane protein complexes mediating passive ion flux across the cell membranes. Every organism has a certain set of ion channels that define its physiology. Dinoflagellates are ecologically important microorganisms characterized by effective physiological adaptability, which backs up their massive proliferations that often result in harmful blooms (red tides). In this study, we used a bioinformatics approach to identify homologs of known ion channels that belong to 36 ion channel families. We demonstrated that the versatility of the dinoflagellate physiology is underpinned by a high diversity of ion channels including homologs of animal and plant proteins, as well as channels unique to protists. The analysis of 27 transcriptomes allowed reconstructing a consensus ion channel repertoire (channelome) of dinoflagellates including the members of 31 ion channel families: inwardly-rectifying potassium channels, two-pore domain potassium channels, voltage-gated potassium channels (K_v), tandem K_v, cyclic nucleotide-binding domain-containing channels (CNBD), tandem CNBD, eukaryotic ionotropic glutamate receptors, large-conductance calcium-activated potassium channels, intermediate/small-conductance calcium-activated potassium channels, eukaryotic single-domain voltage-gated cation channels, transient receptor potential channels, two-pore domain calcium channels, four-domain voltage-gated cation channels, cation and anion Cys-loop receptors, small-conductivity mechanosensitive channels, large-conductivity mechanosensitive channels, voltage-gated proton channels, inositole-1,4,5-trisphosphate receptors, slow anion channels, aluminum-activated malate transporters and quick anion channels, mitochondrial calcium uniporters, voltage-dependent anion channels, vesicular chloride channels, ionotropic purinergic receptors, animal volage-insensitive cation channels, channelrhodopsins, bestrophins, voltage-gated chloride channels H⁺/Cl^- exchangers, plant calcium-permeable mechanosensitive channels, and trimeric intracellular cation channels. Overall, dinoflagellates represent cells able to respond to physical and chemical stimuli utilizing a wide range of G-protein coupled receptors- and Ca²⁺-dependent signaling pathways. The applied approach not only shed light on the ion channel set in dinoflagellates, but also provided the information on possible molecular mechanisms underlying vital cellular processes dependent on the ion transport.

• 한국물환경학회지
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• 제34권6호
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• pp.678-687
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• 2018

The purpose of this study was to understand the unique and complicated feature of urban stream receiving various inflows. The Yangjae stream, the second tier of the Han River, runs through the southern parts of Seoul, Korea and its middle part flows on the boundary of Seoul where land use is actively changing. Stream flow was greatly influenced by rainfall. Other than rainfall events, effluent discharge from wastewater treatment plant (WWTP) comprised 51 % of stream flux. As a result, majority ions water chemistry was changed at the receiving zone of the discharged effluent (Zone A). Its contribution increased to 69.9 % at the second sampling period with low stream flow. In the middle zone, inflows from the northern area, recently developed to a residential district showed low $NO_3-N$ and high $HCO_3$, Ca, $SO_4$, and $SiO_2$ indicating the effects of groundwater and concrete. One inflow (T-8), with extremely high Na and Cl, median $SiO_2$, was assessed to have anthropogenic influence, however its contribution to main stream was under 1 %. Road construction near Y-13 also affected water chemistry leading to the highest Na and Cl concentration. These hydro chemical changes can be critically used to evaluate the changes in water budget and fate of chemicals in a peri-urban watershed occasioned by human activities on the Yangjae.

• 보존과학회지
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• 제32권4호
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• pp.549-560
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• 2016

진안 봉곡도요지 출토 흑유자기에 대하여 과학적 분석과 재현실험으로 재료학적 특성 자료를 제시하고자 한다. 미시적 관찰과 물리적 특성, 화학조성 분석으로 구분하여 실시하였으며, 재현실험은 분석결과에 따라 시판 흑유, 석간주 및 석회석을 사용하여 시편을 제작하고 단면을 관찰하였다. 물리적 특성은 자화 정도에 따라 일부 도편에서 차이를 보이며, 미시적 관찰에서 유약 내에 수지상 등의 결정 조직이 관찰되었다. 열분석에서 $1200^{\circ}C$ 내외에서 발열피크가 확인되고 결정구조분석에서 뮬라이트가 동정되어, 약 $1100{\sim}1200^{\circ}C$의 온도에서 소성된 것으로 판단할 수 있다. 유약의 성분 조성은 타 지역 출토 흑유자기의 유약에 비하여 $Fe_2O_3$의 함량이 약 22%로 높게 나타나며, CaO의 함량은 약 9%로 낮게 나타난다. 재현실험에서 석간주와 석회석의 혼합비에 따라 유약층의 단면에서 출토 도편과 유사한 결정 조직을 이루는 것이 관찰되었다. 이는 산화철이 용융, 응고되는 과정에서 생성되는 것으로 추정된다.

• 대기
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• 제26권3호
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• pp.445-459
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• 2016

Air temperature deviation (ATD) is one of major indicators to represent spatial distribution of urban heat island (UHI), which is induced from the urbanization. The purpose of this study is to evaluate the accuracy of air temperature deviation about Climate Analysis Seoul (CAS) workbench, which had developed by National Institute Meteorological Science and TU Berlin. Comparison and correlation analysis for CAS ATD including meso-scale air temperature deviation, local-scale air temperature deviation, total air temperature deviation, surface heat flux deviation, cold air production deviation among meso-scale numerical modelling variable in 'Seoul Region', micro-scale numerical modelling in 'Detail Region', and CAS workbench variable using observation data in ground stations. Comparison between night time OBS ATD and CAS ATD show that have most close values. Most of observations ($dT_{max}$ and $dT_{min}$) have highly positive ($dT_{SHP}$, $dT_{CA}$, MD, TD, $f_{BS}$, $f_{US}$, $f_{WS}$, $h_B$) and negative ($f_{VS}$, $f_{TV}$, $h_V$, Z) correlations. However, CAS workbench needs further improvement of both observational framework and analytical framework to resolve the problems; (1) night time OBS ATD of has closer values in compare with at high rise mountain area and (2) correlations are very dependable to meteorological scale.

• 상하수도학회지
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• 제25권3호
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• pp.383-390
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• 2011

In this study, a process combined biofiltration with sulfur-utilizing autotrophic denitrification and membrane separation was proposed to examine the efficiency of nitrogen removal. As an experimental device, hollow-fiber module was installed in the center of reactor to generate the flux forward sulfur layer in the cylinder packed with granular sulfur. In addition, a simple module was installed in activated sludge aeration tank which inside and outside of sulfur-using denitrification module was covered with microfilter and the module was considered as an alternative of clarifier. The experiment for developing new MBR process was carried out for three years totally. As the results of first two-year experiment, successful nitrogen removal performance was revealed with lab-scale test and pliot scale plant using artificial wastewater and actual plating wastewater. In this year, pilot scale test using actual domestic wastewater was performed to prove field applicability. As the results, high-rate nitrogen removal performance was confirmed with about 0.19 kg ${NO_3}^--N/m^3$ day of rate. Also significant fouling and pressure increase were not found during the experiment. And, the production ratio of sulfate and the consumption ratio of alkalinity showed a slightly higher value about 311 mg ${SO_4}^{2-}/L$ and 369 mg $CaCO_3$/L, respectively. In conclusion, the developed MBR process can be utilized as an alternative for retrofiting existing wastewater plants as well as new construction of advanced sewage wastewater treatment plants, with cost-effective merit.

• 천문학회보
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• 제36권2호
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• pp.89.1-89.1
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• 2011

We have investigated a coronal jet near the limb on 2010 June 27 by Hinode/X-Ray Telescope (XRT), EUV Imaging Spectrograph (EIS), Solar Optical Telescope (SOT), SDO/Atmospheric Imaging Assembly (AIA), and STEREO. From EUV (AIA and EIS) and soft X-ray (XRT) images we identify the erupting jet feature in cool and hot temperatures. It is noted that there was a small loop eruption in Ca II images of the SOT before the jet eruption. Using high temporal and multi wavelength AIA images, we found that the hot jet preceded its associated cool jet. The jet also shows helical-like structures during the rising period. According to the spectroscopic analysis, the jet structure changes from blue shift to red one with time, implying the helical structure of the jet. The STEREO observation, which enables us to observe this jet on the disk, shows that there was a dim loop associated with the jet. Comparing the observations from the AIA and STEREO, the dim loop corresponds to the jet structure which implies the heated loop. Considering that the structure of its associated active region seen in STEREO is similar to that in AIA observed 5 days before, we compared the jet morphology on the limb with the magnetic fields extrapolated from a HMI vector magnetogram observed on the disk. Interestingly, the comparison shows that the open field corresponds to the jet which is seen as the dim loop in STEREO. Our observations (XRT, SDO, SOT, and STEREO) are well consistent with the numerical simulation of the emerging flux reconnection model.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2020년도 추계국제학술대회
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• pp.61-61
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• 2020

This experiment was carried out using artificial bed soil and LED in the plastic film house(irradiation time: 07:00-17:00/day). Seedlings(n=63 per 3.3 m²) of ginseng was planted on May 17, 2018. LED was combined with red and blue light in a 3:1 ratio and irradiated with different light intensity(40-160 µmol/m²/s). Average air temperature from April to September according to the light intensity test was 20.4℃-20.9℃. Average artificial bed soil temperature was 20.1℃-21.7℃. The test area where fluorescent lamp was irradiated tended to be somewhat lower than the LED irradiation area. The chemical properties of the test soil was as follows. pH levels was 6.6-6.7, EC levels 0.9-1.3 dS/m and OM levels 30.6-32.0%. The available P₂O₅ contents was 73.3-302.3 mg/kg. Exchangeable cations K and Ca contents were higher than the allowable ranges and mg content was high in the fluorescent lamp treatment. The photometric characteristics of LED light intensity are as follows. The greater the light intensity, the higher the PPFD(Photosynthetic Photon Flux Density) value, illuminance and solar irradiation. Fluorescent lamp treatment had high illuminance value, but PPFD and solar irradiation were lower than LED intensity 40 µmol/m²/s treatment. The photosynthetic rate increased(2.0-3.8 µmolCO²/m²/s) as the amount of light intensity increased, peaking at 120 µmol/m²/s, and then decreasing. The SPAD (chlorophyll content) value decreased as the amount of light intensity increased, and was the highest at 36.1 in fluorescent lamp treatment. Ginseng germination started on April 5 and took 14-17 days to germinate. The overall germination rate was 68.8-73.6%. The growth of aerial parts(plant height etc.) were generally excellent in the treatment of light intensity of 120-160 µmol/m²/s. The plant height was 41.9 cm, stem length was 24.1 cm, leaf length was 9.8 cm and stem diameter was 5.6 mm. The growth of underground part (root length etc.) was the best in the treatment with 120 µmol/m²/s of light intensity. Due to the root length was long(24.8 cm) and diameter of taproot was thick(18.7 mm), the fresh root weight was the heaviest at 24.8 g. There were no disease incidence such as Alternaria blight, Gray mold and Anthracnose. Disease of Damping-off caused by Rhizoctonia solani occurred 0.6-1.5% and incidence ratio of rusty root ginseng was 30.8-62.3%. It is believed that the reason for the high incidence of rusty root ginseng is that the amount of field moisture capacity of artificial bed soil is larger than the soil. Leaf discoloration rate was 13.7-32.3%.

• 대한환경공학회지
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• 제28권11호
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• pp.1180-1185
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• 2006

오염된 퇴적물로부터 인 용출 저감을 위한 최적의 capping 소재를 개발하기 위해 lab-scale 실험을 25 L 아크릴 컬럼을 이용하여 실시하였다. 실험에 사용된 퇴적물 내 입도는 8.8 $\Phi$로 매우 세립한 clay로 조성되어 있으며, 유기탄소 함량($C_{org}$)은 2%로 높다. Batch 실험에 사용된 capping 소재는 Brucite($Mg(OH)_2$), Sea sand($SiO_2$), Granular-gypsum($CaSO_4{\cdot}2H_2O$), Double layer(brucite+sand)와 Control을 30일 동안 비교 평가하였다. 실험기간 동안 용출된 인의 flux는 14.6 $mg{\cdot}m^{-2}{\cdot}d^{-1}$, 9.5 $mg{\cdot}m^{-2}{\cdot}d^{-1}$, 5.2 $mg{\cdot}m^{-2}{\cdot}d^{-1}$, 4.2 $mg{\cdot}m^{-2}{\cdot}d^{-1}$, 3.1 $mg{\cdot}m^{-2}{\cdot}d^{-1}$로 Control>Sea sand>Granular-gypsum>Double layer>Brucite 순으로 각각 나타났다. Brucite를 적용한 컬럼의 경우, 인 용출 제어 효율이 70% 이상 높게 나타났으며, Sea sand를 적용한 경우에는 35%의 효율만을 보였다. 특히, Brucite를 적용한 컬럼의 표층 퇴적물내 pH는 $8.0{\sim}9.5$로 다소 높게 유지되었으며, 이러한 효과는 퇴적물을 약알카리성으로 유지하여 황산염환원균이 증식할 수 없는 환경을 조성하여 생물에 독성이 있는 $H_2S$ 발생을 억제시킬 수 있다. Gypsum을 적용할 경우, 퇴적물내 빠른 초기 속성화작용의 진행과 충분한 $SO_4^{2-}$-의 공급으로 methanogenesis 진행를 저하시킬 수 있다. 따라서 Brucite와 Gypsum을 적용할 경우, 퇴적물 내 인의 존재형태가 광물(mineral)의 형태인 $Mg_5(OH)(PO_4)_3$, pyrite, apatite-mineral의 형태로 진행되어 퇴적물로부터 인의 용출을 줄일 수 있다.

• 생물환경조절학회지
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• 제20권3호
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• pp.189-196
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• 2011

Ebb and flow 시스템을 사용한 분화 칼랑코에 재배에서 광도와 양액 농도가 생육, 양분 흡수율 및 배지 내 무기 이온의 집적에 미치는 영향을 구명하기 위하여 본 연구를 수행하였다. 연구 목적을 달성하기 위하여 광도 3수준(PPF 4.26, 5.51, $9.75mol{\cdot}m^{-2}{\cdot}d^{-1}$)과 양액 농도 3수준(EC 1.2, 1.8, $2.4dS{\cdot}m^{-1}$)을 조합하여 요인실험으로 수행하였다. 분화 재배한 칼랑코에의 생육은 광도와 양액 농도에 뚜렷하게 영향을 받았으며, 광도가 높아질수록 생육이 양호하였다. 각 광도 내에서는 양액의 EC를 $1.8\sim2.4dS{\cdot}m^{-1}$의 범위로 조절할 경우 칼랑코에 지상부 생육이 비교적 양호하였지만, EC를 $2.4dS{\cdot}m^{-1}$로 조절한 처리의 생체중, 건물중 및 엽면적이 가장 크게 나타났다. 광도와 양액 농도는 ebb and flow 시스템의 양액 탱크로부터 양분 및 수분 흡수량과 배지 내 무기 이온의 집적에 유의하게 영향을 미쳤지만, 식물체의 무기물 함량에는 뚜렷한 영향을 미치지 않았다. 광도는 양액의 EC에 비해 이온의 흡수율에 미치는 영향이 상대적으로 적었으며, 양액 EC가 높을 수록 $NO_3^-$, P, K, Mg 이온의 흡수율은 높았다. 이상의 연구결과를 고려할 때 ebb and flow 저면 관수 시스템에서 배지 내 무기 이온 집적에 영향을 주는 주 요인은 양액 농도임을 확인하였으며, 광도와 양액의 EC를 이용하여 배지 내 무기 이온의 집적량을 예측하기 위한 회귀식을 제시하였다.