• Nuclear Engineering and Technology
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• v.54 no.4
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• pp.1245-1252
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• 2022

As regulatory bodies require full implementation of security controls in nuclear power plants (NPPs), security functions for critical digital assets are currently being developed. For the ultimate introduction of security controls, not alternative measures, it is important to understand the relationship between possible cyber threats to NPPs and security controls to prevent them. To address the effectiveness of the security control implementation, this study investigated the types of cyber threats that can be prevented when the security controls are implemented through the mapping of the reorganized security controls in RS-015 to cyber threats on NPPs. Through this work, the cyber threat that each security control can prevent was confirmed, and the effectiveness of several strategies for implementing the security controls were compared. This study will be a useful reference for utilities or researchers who cannot use design basis threat (DBT) directly and be helpful when introducing security controls to NPPs that do not have actual security functions.

• Korean Journal of Weed Science
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• v.1 no.1
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• pp.69-77
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• 1981

Six herbicides were evaluated to investigate the phytotoxicity of rice plant and the weeding efficacy influenced by the time of application in mechically transplanted paddy field. The amount of each chemical applied was 3 kg, a. i, /ha. Chlormethoxynil : Rotala indica KOEHNE and Lindernia pyxuiaria PHILCOX were effectively controlled when applied on the 12th day after transplanting (12 DAT) and this herbicide was excellent for the control of Echinochloa crusgalli P. BEAUV, Monochoria vaginalis PRESL and Sagittaria pygmaea MIQ, when applied early (7 days after puddling) but its weeding effect for these weeds decreased greatly as the application time became later. It had a controlling effect for Potamogeton distinctus A. BENN, Cyperus serotinus ROTTB and Scirpus hotarui ROXB at the initial period at the earlier application time. Butachlor was effective in controlling E. crusgalli, R. indica and L. pyxidaria at 12 days after transplanting (DAT) but was not effective in controlling P. distinctus and S. pygmaea even at the early application time. M. vaginalis, C. serotinus and S. hotarui were effectively controlled by the butachlor treatment at 7 days after final puddling (2 DBT-SDAT) but this weeding effect decreased at the late application time. A combination of butachlor and naproanilide excellently controlled E. crusgalli, R. indica, L. pyxidaria and S. pygmaea regardless of the application time. For the control of M. vaginalis, C. serotinus and P. distinctus, the weeding effect of this mixtures was much greater than that of the single treatment of butachlor. Perfluidone was excellent for the control of E. crusgalli, R. indica, L. pyxidaria, M. vaginalis and S. pygmaea at either application time tested. P. distinctus, C. serorinus and S. hotarui could be controlled by this chemicals until the time of first observation (23 DAT) but the effect for these weeds somewhat decreased as time passed. The effect of pyrazolate on E. crusgalli, M. vaginalis, S. hotarui and P. distinctus was very excellent regardless of the application time but R. indica and L. pyxidaria could not be completely eliminated by this chemical. This chemical was effective in controlling C. serotinus when applied at 7-9 days after final puddling and showed a controlling effect for S. hotaruionly at the initial period. Piperophos + dimethametryn was very excellent for the control of all the annual weeds and P. distinctus. It showed a controlling effect on S. pygmaea, C. serotinus and S. hotarui only at the initial period. There was no difference in the effects on phytotoxicity and yield between chlormethoxynil and pyrazolate at either times of application tested. The later the application time was, the less the phytotoxicity of butachlor and piperophos+dimethametryne was. The phytotoxicity of butachlor + naproanilide and perfluidone decrease in the plots treated at the later application time. When the last two chemicals were treated at 2 days before transplanting (DBT) the yield decreased as compared with the hand weeded plot.

• The Korean Journal of Ecology
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• v.24 no.1
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• pp.19-26
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• 2001

Tributyltn, triphenyltin and their degradation products were quantitatively determined in sediments, seawater, and oysters (Crassostrea gigas) collected from Okpo Bay, Korea where a huge shipyard was located. The concentrations of TBT in sediment and oyster were in the range of 5∼2,050 ng/g and 387∼1,190 ng/g (astin on a dry weight basis), respectively. In seawater, it ranged from 19 to 84 ng/ℓ The distribution of TBT compound showed negative gradient from inner to outer bay, which indicates that the shipyard is the point source of TBT contamination in the bay. The contribution of TBT to butyltin concentration in sediment was above 57%. The pattern of TBT distribution was influenced by waterbreak transected the bay. TPhT concentration in oyster ranged from nd (not detected) to 52 ng Sn/g dry wt., whereas that in sediment and seawater was below detection limit. The biological concentration factor (BCF) in oyster was 1.1×10⁴.

• Journal of Environmental Science International
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• v.11 no.8
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• pp.793-800
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• 2002

Butyltin (BT) compounds were measured in seawater, sediment, sediment core, settling solids, and plankton from Gwangyang Bay in 2001, Tributyltin (TBT) was detected in seawater from 1 out of the 7 seawater sampling sites and in sediment from 18 out of the 35 sediment sampling sites. The highest concentration of TBT was found in the sediment from the site near Yeosu Harbor (53 ng Sn/g dry wt), acting as the point source for TBT The mean concentrations of TBT were in the order of plankton> settling solids> sediment. The degradation indexes ([DBT]+[MBT]/[TBT]) for the plankton were less than 1, indicating the possibility of recent inputs of TBT. The indexes for the sediment and settling solids ranged from 1.14 to 8.73. The composition of the BT compounds found in the settling solids was similar to that found in the sediment. The vertical profile of the total BT compounds in the sediment was characterized by an abrupt decline from the surface. However, no butyltin compounds appeared below a depth of 10 cm, corresponding to the 1980s. Accordingly, the current results demonstrated that the levels of all butyltin species in the environment of Gwangyang Bay were relatively lower than those in other polluted coastal areas. The vertical profile also suggested a fairly recent history for the down-core.

• Journal of Science and Technology Studies
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• v.15 no.2
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• pp.33-64
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• 2015

World Wide Views (WWViews) on Climate and Energy was an experiment of public deliberation which was held in 77 countries with over 10,000 global citizens on June 6, 2015. The coordinator of this project (the Danish Board of Technology with Missions Publiques and the French National Commission for Public Debate) developed the overal procedure, and local partners implemented the actual events in each country on the same day. The coordinator gathered the results of the events from all local sites in order to submit them as global citizens' voice to the COP21 negotiations at the United Nations Framework Convention on Climate Change (UNFCCC) in Paris. This study examines the extent to which such new method of WWViews, standardized at global level to be implemented in different local contexts, achieves its quality of public deliberation (representativeness, transparency, impartial inclusion, deliberativeness, influence) by evaluating the Korean WWViews held in Seoul.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.16 no.6
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• pp.590-605
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• 1987

The purpose of this study was to investigate thermal environmental factors, thermal clothing properties, and thermal sensation of the office workers in four selected office buildings in Seoul, and to determine the effect of thermal environmental factors and clothing insulation to the thermal sensation of the subjects. The subjects selected from each office were 5 males and 5 females at a time. Thermal environmental factors(DBT, GT, RH, MRT, $ET^{\ast}$) and clothing variables such as clothing weight per body surface $area(g/m^2)$ and estimated clothing insulation values(clo) were significantly different among each seasons(p<0,001). Means of $ET^{\ast}$ and estimated clothing insulation values of each season were as follows; Winter; $20.84^{\circ}C$ $ET^{\ast}$ with 0.72 clo for male and 0.79 clo for female Spring and fall; $23.65^{\circ}C$ $ET^{\ast}$ with 0.59 clo for male and 0.68 clo for female Summer; $26.00^{\circ}C$ $ET^{\ast}$ with 0.47 clo for male and 0.53 clo for female. In comparison these data with ASHRAE Standard, the subjects were predicted to feel comfort-able in spring and fall, and slightly hot in summer and slightly cold in winter because of high and low clo respectively. But the result of this survey showed more than $80\%$ of the occupants were thermally comfortable at a given environmental temperature and clo.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.4
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• pp.291-298
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• 2001

Seawater, sediment and biota in the Kwangyang Bay were analyzed by gas chromatography/quartz furnace atomic absorption spectroscopy (GC-QFAAS) to investigate concentrations and distribution pattern of butyltin compounds (TBT, DBT, MBT) during February, April and July, 1996, Marine biota analyzed were Tapes japcnicus and Crassostrea gigas. The concentrations of tributyltin (TBT) in seawater were in the range of ND-15.7 ng/L for the surface and ND-68.5 ng/L for the bottom. The highest concentration of TBT in seawater was detected in April for the both, surface and bottom water. The maximum value of $TBT_{(bottom)}/TBT_{(surface)}$, 3.6 in April showed the increased input of TBT from the surface water in April compared to February (2.1) and July (0.9). The concentrations of TBT in the sediment were in the range of ND-8.5 ng/g dry wt. The highest concentration of TBT in the sediment was measured in July, This result seems to attributed to the removal of TBT from water column via sorption onto particulate matters to the relatively undisturbed underlying sediment and increased input of TBT by increased fluxes of detritus of marine plankton after spring bloom, in July. The mean values of partitioning coefficient ($K_d$) of TBT between seawater and sediment were $3.0\times10^3$(February), $7.4\times10^3$(April) and $9.4\times10^3$(July). The concentrations of TBT in biosamples were in the range of ND-93.30 ng/g dru wt. (T. japonicus) and ND-138.53 ng/g dry wt. (C. gigas). The seasonal variation of TBT contents in biota was remarkable. The $K_d$ (biological concentration factor) was $7-41\times10^3$ for T. japonicus. and $5-34\times10^3$ for C. gigas. The measured TBT concentrations in seawater in the study area was sufficient to cause the imposex of shellfish and to retard the growth of aquatic organisms including oyster upon chronic exposure.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.20 no.4
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• pp.360-369
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• 1987

The relationship between the catches of tuna and hydrographic conditions in South-East Pacific region (latitude $5^{\circ}N-12^{\circ}S$, longitude $135^{\circ}W-115^{\circ}W$) was investigated by using the catch data of tuna and Digital Bathythermograph (DBT) data from December 9, 1980 to April 2, 1981. The results are as follows : The study area were located in South Eguatorial Current regions including equatorial upwelling regions in $5^{\circ}N\;to\;12^{\circ}S$. The horizontal mean temperature at the depth of 10m on the first quarter months in the study area was about $25^{\circ}C$C and the salinity of those fishing areas ranged from 34.8 to $35.0\%_{\circ}$. Yellowfin tuna and bigeye tuna were mainly caught in SW vertical temperature profile type, which the depth of thermocline ranged from loom to 300m, and temperature difference of thermocline was about $12^{\circ}C$. The deeper the depth of thermocline, the more the catches of tuna. While albacore tuna was caught well in SS vertical temperature profile type which the temperature of thermocline ranged from $9^{\circ}\;to\;26^{\circ}C$ and its gradient was very smooth. The depth of 1 ml/l surface of dissoved oxygen content ranged from loom to 200m in the South-East Pacific between longitude $140^{\circ}W-100^{\circ}W$, but it was shallower than 100 m near the North-South American continent. The catches of bigeye tuna were larger than those of yellowfin tuna in South Equatorial Current region. As approaching to the South and North American continent, the catches of yellowfin tuna and bigeye tuna decreased because the thermocline becomes shallower and steeper and the depth of the 1 m1/1 surface of dissolved oxygen content became shallower.

• Journal of Soil and Groundwater Environment
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• v.10 no.3
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• pp.38-45
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• 2005

The feasibility of stimulating in situ aerobic cometabolic activity of indigenous microorganisms was investigated in a trichloroethylene (TCE)-contaminated aquifer. A series of single-well natural drift tests (SWNDTs) was conducted by injecting site groundwater amended with a bromide tracer and combinations of toluene, oxygen, nitrate, ethylene and TCE into an existing monitoring well and by sampling the same well over time. Three field tests, Push-pull Transport Test, Drift Biostimulation Test, and Drift Surrogate Activity Test, were performed in sequence. Initial rate of toluene degradation was much faster than the rate of bromide dilution resulting from natural groundwater drift, indicating stimulation of indigenous toluene-oxidizing microorganisms. Transformation of ethylene, a surrogate probing overall activity of TCE transformation, was also observed, and its transformation results in the production of ethylene oxide, suggesting that some tolueneoxidizing microorganisms stimulated may express a orthomonooxygenase enzyme. Also in situ transformation of TCE was confirmed by greater retardation of TCE than bromide after the stimulation of toluene-oxidizing microorganisms. These results indicate that, in this environment, toluene and oxygen additions stimulated the growth and aerobic cometabolic activity of indigenous microorganisms expressing orthomonooxygenase enzymes. The simple, low-cost field test method presented in this study provides an effective method for conducting rapid field assessments and pilot testing of aerobic cometabolism, which has previously hindered application of this technology to groundwater remediation.

• Korean journal of applied entomology
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• v.4
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• pp.47-50
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• 1965

Many of the chlorophenol derivatives are widely used as insecticides, herbicides and plant growth regulators. The function and use of these chemicals would be different according to the number of chlorine and their chemical structures. It was reported in this article that 1) Bis(trichlorophenoxy) ethane was synthesized with 2 mol-trichlorophenol and 1 moi-dibromoethane in 2 moi-Sodium hydroxide alcohol solution, and 3) the insecticidal activity of Bis(trichlorophenoxy) ethane was compared with Phenkapton, Tedion V-18, BHC, and DDT, on Citrus red mite, Bombix mori (Silk worm), and Daikon leaf beetle(Phaedon brassicae) 3) The toxicity of Bis(2, 4, 5-trichlorophenoxy) ethane and Bis(2, 4, 5-trichlorophenoxy) ethane was studied on mice. The following results were obtained. 1) Yield of Bis(2, 4, 5-trichlorophenoxy) ethane, $50.06\%$, m.p. $157-159^{\circ}C$, and yield of Bis(2,4, 6-trichlorophenoxy) ethane, $32.60\%$, m.p. $162-163^{\circ}C$. 2) Insecticidal activity of Bis(2, 4, 5-trichlorophenoxy) ethane to Citrus red mite is stronger than that of Tedion V-18, and weaker than that of Phenkapton. 3) Insecticidal activity of Bis(2, 4, 5-trichlorophenoxy) ethane to Bombix mori is weaker than those of BHC and DDT. 4) Insecticidal activity of Bis(2. 4, 5-trichlorophenoxy) ethane to Daikon leaf beetle proved to be ineffective. 5) Five rams of Bis(2, 4, 5-trichlorophenoxy) ethane and Bis(2, 4, 6-trichlorophenoxy) ethane pet kg of body weight respectively were given to mice orally, and none of the mouse was killed by it after a period of 72 hours. Therefore it seems that there is almost no toxicity.