• The Korean Journal of Pesticide Science
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• v.13 no.4
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• pp.209-215
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• 2009

This study was performed to produce the processing factors of pesticides in dried carrot. It is essential data for establishing the maximum residue limits (MRLs) of pesticides in dried carrot. The target pesticides were azinphos-methyl, chlorpyrifos, captan, endosulfan and triclorfon. These pesticides are included Korea's MRL list in carrot and USA's MRL list in dried foods. To infiltrate these pesticides up to each MRL level in carrot, the dipping test was performed in laboratory. Also, the supervised residue trial of the pesticide for carrot was conducted in the green house to recognize the field trial's tendency. In the dipping test in laboratory (including drying examination), the processing factors of the carrot at various concentrations and temperatures could be evaluated. In field test, the processing factors were 5.9 for azinphos-methyl, 1.7 for captan, 7.6 for chlorpyrifos, 6 for endosulfan, 0 for trichlorfon, respectively. The dipping test in laboratory on various kinds of conditions showed more precise processing factors than field trial. The processing factors obtained from the dipping test of carrot were 0~4.7 at the various concentration of the pesticides, and 0~6.7 at various drying temperature. The lower level processing factors were 0~0.6 for trichlorfon and the higher level were 3.0~5.8 for chlorpyrifos. The highest processing factor was 9.1 for captan.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.4
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• pp.10-18
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• 2018

The primary purposes of this study are to understand a fundamental aspect of current uniformity around a reinforcing bar (rebar) in cement mortar, and to develop an accurate monitoring method in a wet-dry cycling process with the alternative current (AC) impedance method. Three cement mortar specimens with two embedded rebars were prepared in the laboratory. As a main variable, the distance between two rebars was designed to be 10, 20 and 30 mm with the same thickness of 20 mm. To simulate the corrosion of rebars in concrete structures in a marine environment, three cement mortar specimens were exposed to 15 wet-drying cycles (24-hour-immersion in seawater and 48-hour-drying in a room temperature) in the laboratory. It was observed that the potential level shifted to a noble value during corrosion potential monitoring, which is attributed to acceleration of dissolved oxygen diffusion at the drying process. AC impedance was measured in a frequency range from 100 kHz to 1 mHz on a wet-drying process. A theoretical model was proposed to explain the interface condition between the rebars and cement mortar by using the equivalent circuit consisting of a solution resistance, a charge transfer resistance and a CPE (constant phase element). It was observed that the diffusion impedance appeared in a low frequency range as corrosion of rebars progresses. At the drying stage of the wet-drying cycles, the currents line for monitoring tended to be non-uniform at the interface of rebar/mortar, being phase shift, ${\theta}$, close to $-45^{\circ}$.

• Journal of Energy Engineering
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• v.28 no.3
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• pp.10-17
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• 2019

According to South Korea's policy of supplying eco-friendly hydrogen vehicles, related industries are actively conducting research on the development of hydrogen cars and hydrogen charging station infrastructure. On the other hand, there is a lack of empirical research and assessment of the risk of non-metallic materials (such as liners, seals, gaskets) for classified materials that directly affect the durability and reliability of hydrogen vehicles and hydrogen charging stations. In this study, the risk factors for liners and seals of non-metallic parts used in high-pressure hydrogen installations were derived using FMEA, and the RPN values were calculated by converting the severity, frequency of occurrence and degree of detection into scores. The maximum value of the RPN 600, minimum value 63, average value 278.5 was calculated and periodic control of the liner and seal was identified as important. In addition, through hydrogen soakage and oxygen aging tests for non-metallic rubber products, physical test values that can be used as basic data were presented.

• Journal of Navigation and Port Research
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• v.34 no.10
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• pp.787-792
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• 2010

It is necessary to predict the penetration of chloride ions for designing RC construction in marine environments. However, it takes a long time to obtain chloride migration coefficients. Therefore, the rapid chloride penetration test (RCPT) is generally used to shorten the test time. But there is a difference between chloride migration coefficients determined by rapid chloride penetration tests and those based on exposure in marine environments. In this study, we evaluated the effect on the chloride ion migration coefficient caused by a change in voltage and NaCl concentration. We also compared the relationship between the chloride ion migration coefficient by RCPT and that by exposure in marine environments. As a result of the experiments, we found that there is only a small change in the experimental factors based on changes in voltage and NaCl concentration and since they are so small, we can conclude that they are in the range of experimental error and test results from chloride ion migration coefficients by RCPT and exposure were very different from each other. In the exposure experiments, when the water-cement ratio was increased, the smaller fine air gaps in concrete affected the chloride ion migration coefficient.

• Korean Journal of Environment and Ecology
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• v.29 no.6
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• pp.842-849
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• 2015

This study investigated the effects of rare-earth fertilizer on the shoot cuttings' rooting of Vitex rotundifolia L. and Tamarix chinensis Lour. The shoot cutting test was carried in 2008 and the main results are summarized as follows. The rate of rooting and the average roots increased in both number and length when rare-earth fertilizer is treated in V. rotundifolia and T. chinensis in comparison to those of the untreated control plot. In particular, when rare-earth fertilizer is diluted with water 1/2500, the rooting outstandingly increases. This result is almost similar to the effect of the rooting stimulant, IAA. Although there is no differentiation in its rooting rate according to the density, the rooting of T. chinensis shows a 100 percent effect on in the entire treated plot but not in the untreated control plot, so it is usable as a rooting stimulant. As for shoot cuttings' rooting, depending on the time immersed in diluted solution of rare-earth fertilizer, both V. rotundifolia and T. chinensis showed relatively higher percentages in all treatment plot immersed for 60 minutes than for 10 minutes. In conclusion, considering the results of the rooting percentage and the average number and length of roots of V. rotundifolia and T. chinensis, the shoot cuttings' rooting appeared higher in percentage when they were immersed in the rooting stimulant for sixty minutes with a lower density than 1/2500. This result shows that rare-earth fertilizer can be utilized as an alterative for IAA rooting stimulants currently available in the market.

• Journal of fish pathology
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• v.10 no.2
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• pp.143-152
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• 1997

The effect of $\beta$-glucan as an immunostimulant to increase resistance to bacterial diseases by enhancing non-specific defense mechanism in rockfish (Sebastes schlegeli) was examined by oral and bath administration. After oral or bath administration with $\beta$-glucan, the injection challenges with Vibro ordalii, Staphylococcus epidermidis and Edwardsiella tarda were performed to assess $\beta$-glucan efficacy. After injection of V. ordalii, oral administration for 30 days with 1% $\beta$-glucan showed 25% of survival rate. But all control fish died within 3 days after the injection. After injection of S, epidermidis, oral administration group for 20 and 30 days showed a remarkably increased survival rate of 95%. But oral administration of $\beta$-glucan to rockfish did not induce protection against experimental E. tarda infection. $\beta$-Glucan bath administration with or without formalin-killed V. ordalii showed that no protection was observed at 10 days after challenge. The results show that $\beta$-glucan to rockfish was effective to increase survival rate of bacterial infections of S. epidermidis and V. ordalii but not against E. tarda.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 1999.05a
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• pp.2-2
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• 1999

금속재료의 표면 특성을 높이기 위해서 여러 표면처리 방법들이 사용되어져 오고 있다. 그 중 용사법에 의한 코팅방법이 최근의 현저한 기술적인 진보와 새로운 용사재료의 개발 등에 의해 여러 분야에 널리 응흉되고 있다. 일반적으로 이 용사법에 의한 코팅층은 다리, 선박 등의 대형 구조물에 대한 내식성 향상뿐만 아니라 자동차 및 항공기 부품, 핵 반응기 등의 코팅부에 널리 이용되고 였다. 특히 해수분위기에서 주로 사용되는 설비의 내식성을 향상시킬 목적으로 사용되 는 알루마늄 및 아연 합금의 용사 코팅층은 대부분의 경우 건조한 분위기보다는 수분이 많은 수용액 환경 하에서 사용되므로, 사용 환경 중에서 용사피막의 내식성을 조사하는 연구가 요구되고 있다. 사용되는 환경하에서의 침지시험에 의한 방법도 중요하지만, 가속화된 전기화학측정에 의한 방법 또한 이용된다. 열용사법에 의한 코팅층의 전기화학적 특성을 알아보기 위해서 3.5 % NaCI 수용액 내에서 AI 5 5083 모재와 Al-2%Zn 합금의 용사 코팅층 각각에 대한, 그리고 AI 5083 모재 위 AI-2%Zn 용사층이 코팅된 경우에 대한 분극거동과 침지시간에 따른 부식전위 및 분극저항성의 특성변화, 표면의 임피던스특성 변화 등을 측정하였다. 이 결과 모재에 대한 코팅층의 희생양극성올 판단할 수 있고, 모재/코팅 사스템의 분극거동은 혼성전위이론(mixed-potential theory)에 의해 결정되었다. 용사 코팅층이 박리되어 모재가 일부 드러난 경우를 모사한 시험편올 제작하고, 시험편 표면의 각 위치에 따라 부식전위 분포를 측정하였다. 그리고 측정 데이터를 기초로 표면의 상태변화를 모사하여 용사코팅에 의한 표면에서의 방식전위분포를 시율레이션하였다. 이와 같은 표면에서의 방식전위분포 해석을 통하여, 코팅층의 희생양극성에 의한 모재의 방식범위를 판단할 수 있다.의 비저 항을 갖는 철 박막에서도 99.9% 순도의 철을 타켓으로 하여 증착된 막은 일반 저탄소 강을 타켓으로 하여 증착된 막보다 훨씬 낮은 부식속도를 보였다.TEX>$He/O_2/Ar/N_2$의 gas를 사용 한 atmospheric pressure plasma cleaning 과 $Ar/O_2$의 gas를 사용한 ICP cleaning에서 이 차전자방출계수(SEEC)가 약 1.5~2.5배 증가된 것을 알 수 있었다. 저지능 등을 평가하여 각 실험결과를 비교분석하여 보았다. 수록 민감하여 304 의 IGSCC 와 매우 유사한 거동을 보인다. 본 강연에서는 304 와 600 의 고온 물에서 일어나는 IGSCC 민감도에 미치는 환경, 예민화처리, 합금원소의 영향을 고찰하고 이에 대한 최근의 연구 동향과 방식 방법을 다룬다.다.의 목적과 지식)보다 미학적 경험에 주는 영향이 큰 것으로 나타났으며, 모든 사람들에게 비슷한 미학적 경험을 발생시키는 것 이 밝혀졌다. 다시 말하면 모든 사람들은 그들의 문화적인 국적과 사회적 인 직업의 차이, 목적의 차이, 또한 환경의 의미의 차이에 상관없이 아름다 운 경관(High-beauty landscape)을 주거지나 나들이 장소로서 선호했으며, 아름답다고 평가했다. 반면에, 사람들이 갖고 있는 문화의 차이, 직업의 차 이, 목적의 차이, 그리고 환경의 의미의 차이에 따라 경관의 미학적 평가가 달라진 것으로 나타났다.corner$적 의도에 의한 경관구성의 일면을 확인할수 있지만 엄밀히 생각하여 보면 이러한 예의 경우도 최락의 총체적인 외형은 마찬가지로 $\ulcorner$순응$\lrcorner$의 범위를 벗어나지 않는다. 그렇기 때문에도 $\ulcorner$순응$\lrcorne

• Korean Journal of Weed Science
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• v.8 no.1
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• pp.45-52
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• 1988

A serial study on differential response in absorption and translocation of $^{14}C$-bensulfuron-methyl was conducted by use of a group of selected rice cultivars as the tolerant or the susceptible to bensulfuron-methly. Trial 1. Differential Response in Absorption and Translocation of Selected Cultivar Group. The susceptible cultivar group has reached as higher rate as 102%, 113%, 115%, 127% and 113% of the tolerant cultivar group in root absorption per seedling, per unit dry weight, and the rate of translocation from bottom to shoot, respectively. Trial 2. Differential Response in Absorption and Translocation of Selected Rice Cultivar as Affected by Exposed Time of Root Portion upto 48 hrs. ${\bullet}$ Regardless of leaf stage of experimented plants, the amount of absorption per seedling and per unit dry weight has reached rather higher in the susceptible(cv. IR 1846) than the tolerant (cv. Chinsurah Boro II). However, separating by portions, the tolerant was realized higher rate of aborption in root but the susceptible in shoot, respectively. ${\bullet}$ Translocation rate from root to shoot, namely the individual seedling based rate of radioactivity in shoot to total radioactivity, was significantly higher in the susceptile than the tolerant. ${\bullet}$ Depending on higher rate of seedling growth at the time of chemical treatment, the susceptible (cv. IR 1846) was seemed more sensitive even at equivalent rate of absorption and translocation.

• Korean Journal of Weed Science
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• v.8 no.1
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• pp.37-44
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• 1988

A serial study on differential response in absorption and translocation of $^{14}C$-oxyfluorfen was conducted by use of a group of selected rice cultivars as the tolerant or the susceptible to oxyfluorfen. Trial 1. Differential response in absorption and translocation of selected cultivar group. The susceptible cultivar group has reached as higher rate as 209%, 193%, 344%, 204% and 152% of the tolerant cultivar group in root absorption rate per unit dry weight, lower-shoot absorption rate, higher shoot absorption rate, whole amount of absorption, and the rate of translocation from bottom to shoot, respectively. Trial 2. Differential Response in Absorbtion and translocation of selected cultivar as affected by exposed portion and time. ${\bullet}$ Regardless of cultivar, the rate of root absorption has effectively realized but the translocation was significantly limited. ${\bullet}$ Lower portion of shoot has also achieved a higher amount of absorption but the translocation was very limited. ${\bullet}$ By relaying the exposure time. the amount of root absorption was ted increasing, and persistent absorption was rather effective in the susceptible (cv. Mushakdanti) cultivar than the tolerant (cv. Chokoto). ${\bullet}$ Translocation of oxyfluorfen from shoot to root was tended to easily attaining in both cultivars.

• Journal of the Korean Wood Science and Technology
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• v.30 no.2
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• pp.172-179
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• 2002

In this study, two materials treated with a flame retardant were examined for their fire resistance. The first, MDF (medium density fiberboard) was overlaid by an oak sliced veneer, which was either treated by soaking in a 6wt.% solution of flame retardant chemicals (pentabromine-chlorinated paraffin) or non-treated and then was coated with either a flame retardant polyurethane coating or with a common polyurethane coating. The second material, Pinus koraiensis penal was either treated by a spray treatment using a flame retardant solution or non-treated and then was coated with either a flame retardant polyurethane coating or with a common polyurethane coating. Pentabromine-chorinated paraffin chemicals were added (6 part of urethane resin) as the flame retardant chemicals in the polyurethane coatings. In the fire resistance test, the th𝜃(℃·min) decreased with the flame retardant treatment or/and the flame retardant coatings, compared to the untreated sample Weight loss (%) decreased with the flame retardant treatment or/and the flame retardant coatings. The ignition time (sec.) increased and the residual flame time (sec.) decreased with the flame retardant treatment or/and flame retardant coatings. Therefore, the flame retardant treatment or/and flame retardant polyurethane coatings have excellent incombustibility.