• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.153-154
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• 2023

Neglected buildings for long period can seriously reduce the durability of the building due to rust in rebars and deterioration in concrete quality due to exposure to outside air, and the seriousness of suspended buildings such as safety accidents and social crimes is emerging due to poor management. In this study, various problems such as the occurrence of safety accidents were analyzed through a fact-finding survey of buildings that have not been maintained due to long-term neglect in all areas of Jeju. In order to reuse a building that has been discontinued, the safety of the building structure itself must be checked. After securing safety through durability investigation, construction should be resumed or converted into a normal building through re-purposing, dismantling, remodeling, etc.

• The Korean Journal of Pesticide Science
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• v.7 no.4
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• pp.302-309
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• 2003

Disease control activities of 230 triazolyl quinoline derivatives were investigated against six plant diseases such as rice blast, rice sheath blight, tomato gray mold, tomato late blight, wheat leaf rust (WLR) and barley powdery mildew (BPM). New triazolyl quinolines, KSI-4315 and KSI-4317 exhibited a great in vivo control activities against WLR and BPM, and then were selected for further tests such as preventive, curative, systemic, and persistence against WLR and BPM. The KSI-4315 and KSI-4317 contained MeS moiety and MsO moiety in carbon 4-position, respectively. They possessed both preventive activity and curative activity against WLR and BPM. KSI-4317 showed the better control activity than KSI-4315 against BPM, while KSI-4315 represented the better antifungal activity against WLR. Good persistence of KSI-4315 and KSI-4317 were also observed against WLR and BPM. Persistence of KSI-4315 was similar to that of KSI-4317 on WLR, but KSI-4317 was superior to KSI-4315 on BPM in its persistence. Systemic disease control of KSI-4315 and KSI-4317 was investigated by examining translaminar activity from leaf-under-surface to leaf-upper-surface, systemic activities by leaf to leaf movement and the effect of drenching treatment. Systemicities of KSI-4315 and KSI-4317 were not observed in wheat, but KSI-4317 showed more predominant systemicity than KSI-4315 in barley. These results suggest that KSI-4317 would potentially control WLR and BPM in the fields.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.2
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• pp.201-207
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• 1987

This experiment was conducted to identify the superior corn hybrids for silage production and to determine the combining ability of their parental inbred lines. A 7-entry diallel cross was evaluated for grain and stover yields, and agronomic characters under 3 different seasons. Hybrids Hi34 x Tx601, Hi26 x Hi34, and Hi29 x Hi34 showed high total dry matter yields. In general, late maturing hybrids had higher grain and silage yields than early maturing hybrids. Leaf area index was correlated with grain and stover yields. Rust rating was negatively correlated with yields and all characters, indicating that rust (Puccinia sorghi) was one of the major factors affecting yields. Diallel analysis showed that inbred Hi34 which was late in maturity and resistant to rust was the best combiner for both grain and silage yields. General combining ability (GCA) and specific com-bining ability (SCA) effects for yields and other characters were significant, suggesting that both additive and non-additive gene effects are involved for those characters. Ratio of GCA/SCA mean squares showed that GCA effects were more important than SCA effects for yields and other characters. GCA x season and SCA x season interactions were significant for grain and stover yields, revealing that gene effects were not stable for those yields under dissimilar environments.

• Corrosion Science and Technology
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• v.8 no.2
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• pp.53-61
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• 2009

In this study, both evaluations by visual imaging for exterior view of coating and by EIS were executed for epoxy primer coated specimens deteriorated by accelerated test, and comparison and analysis were carried out for 2 evaluation methods. In the comparison between total damaged area ratio acquired by image processing method and deterioration point, higher deterioration points were appeared for rusted specimens than for non-rusted specimens. It is attributed that deterioration point per unit area ratio given for rust is higher than for peeling. In the comparison between total damaged area ratio and EIS result, impedance of coating was largely decreased as about TEX>$10^4{\Omega}{\cdot}cm^2$ or less when rust area ratio is more than about 0.1%, and blistering area ratio is more than about 3%. Charge transfer resistance ($R_{ct}$) and double layer capacitance ($C_{dl}$) values were appeared for all specimens except 2 ones, which shows that water is accumulated and steel substrate is corroded at coated film-steel interface. In the comparison between deterioration point and EIS result, more than 10 points as deterioration point were given for specimens of below $10^6{\Omega}{\cdot}cm^2$ of impedance at low frequency. For specimens deteriorated by NORSOK cyclic test, impedance was lowest of all, though deterioration point was not high. It is thought to be attributed that coating system and accelerated deterioration condition of cyclic tested specimens were different from those of main specimens. From the result, it is thought that coating resistance can be relatively more decreased than deterioration degree estimated from exterior view under more severe corrosion environment or in the present of more complex deterioration factors.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.7
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• pp.1-8
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• 2019

The primary purposes of this study are to understand a fundamental effects of electro-deposition on reinforcing steel in saturated Ca(OH)2 electrolyte, and evaluate the corrosion rates of rebars under cyclic 3wt.%NaCl immersion and dry corrosion environment. The three cement mortar specimens with cover thickness 5, 10 and 30mm, were prepared in the experiment. To monitor the corrosion rates of rebars in mortar, the three cement mortar specimens were exposed to 110 wet-drying cycles(8-hour-immersion in 3wt.%NaCl and 16-hour-drying in a room temperature) in the laboratory. During the wet-dry cycles, the polarization resistance, Rp, and solution resistance, Rs, were continuously measured. The instantaneous corrosion rates of rebars on the effect of electro-depositing with sat. Ca(OH)2 electrolyte were estimated from obtained R-1p and degrees of wetness were estimated from Rs values. From the experimental results, the corrosion rates of rebars were greatly accelerated by wet/dry cycles. During the mortars exposed to drying condition, the large increases in the corrosion rates were showed at all rebar surfaces in three mortar specimen, attributed from the accelerated reduction rates of dissolved oxygen in drying process. However, the corrosion rates on rebar surface electrochemically deposited with sat. Ca(OH)2 electrolyte showed the clear decreases, caused by calcium deposits in the porous rust layer.

• Korean Journal of Medicinal Crop Science
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• v.5 no.3
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• pp.206-210
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• 1997

The pathogenic fungi associated with blight of leaf and stem in peony were leaf spot (Alternaria sp.), powdery mildew (Erysiphe aquilegiae) and rust (Cronartium flaccidum). The infection of leaf spot and powdery mildew begins from late April to midMay and rust was infected in early June. Blight time of aerial part in peony started from late May and the ratio of blight on leaf and stem was more than 50% in late Aug. Yields of root by the incidence time of blight of leaf and stem were 69.1% in late June, 65.4% in late July and $87.6{\sim}92.7$% in August and September. The number of root of more than 10mm in root diameter blighted in late June and July was much lower than in August, but the paeoniflorin content in the former was much higher than the latter.

• The Korean Journal of Pesticide Science
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• v.14 no.4
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• pp.401-406
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• 2010

This study was conducted to investigate the control effects of the environmental-friendly materials against major diseases of pear and to elucidate factors related to spore disperse of pear scab and pear rust. Spore disperse was deeply related ambient temperature in the early stage of disease occurrence and the maximum spore disperse was affected greatly by the air humidity, Percent of infected leaves of pear scab in plot treated with Trichoderma harzianum-YC459 was 29.3% and 43.3% in plot treated with Sulfur-80%. Two formulations above-mentioned were less effective to control pear scab than the chemical pesticide, hexaconazole. Control effect in plots single- and mixed-treated with Trichoderma harzianum-YC459, Sulfur-80% and hexaconazole against pear scab were compared with that in plot treated with chemicals by conventional application schedule in pear orchard. The incidence of pear scab was lower in plot treated with the environmental-friendly materials than that of untreated plot. However there was no significant difference among the treatments at the 5% level. Application of Sulfur-80% reduced significantly the incidence of pear scab (7.8%) compared to that (10.3%) in plot treated by conventional application schedule in organically cultivated pear orchard. Alternative application of Trichoderma harzianum-YC459 and Sulfur-80% (4.3%) suppressed the incidence of pear rust than that (7.1%) in plot treated by conventional application schedule in organically cultivated pear orchard.

• Journal of Korean Society of Steel Construction
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• v.16 no.4 s.71
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• pp.415-423
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• 2004

To investigate the long-term corrosion resistance of an uncoated weathering steel, an important outdoor constructional steel material, skyward surfaces of the weathering steel and a control steel initially exposed to rural and industrial atmospheres for 9 years were electrochemically tested in neutral artificial rain in terms of electrochemical potentials, impedances, and anodic potentiodynamic polarization curves. Their results were then discussed. A quite passive and stable rust layer to the artificial rain was well formed on the skyward surface of the weathering steel exposed to the industrial and rural atmospheres, and its corrosion rate in the artificial rain was measured to be about a low $3{{\mu}m}/y$. Continuous immersion of all the weathered surfaces in the artificial rain revealed the gradual degradation of the weathered corrosion layers on the steel, resulting in a cathodically controlled corrosion of the substrate steel by the electrochemical measurements. Alloy components of the weathering steel were found to retard the degradation of the weathered corrosion layers on the steel in the artificial rain. For better corrosion evaluation of the weathering steel, more electrochemical measurements of surfaces that have been exposed for more than 9 years to more closely simulated atmospheric waters are needed. These measurements are almost non-destructive and can provide online and in situ information on the corrosion rate, the development of corrosion and the conditions of rust layers on any interested surface and at any exposure time of the steel, so they can be effectively applicable to the corrosion evaluation of steel structures such as bridges, towers, and architectures by forming an electrochemical cell on an interested structural surface and by using a portable electrochemical instrument.

• Applied Biological Chemistry
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• v.44 no.3
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• pp.191-196
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• 2001

${\alpha},{\beta}$-Unsaturated carboxanilides 5 with trifluromethylated dihydro-1,4-oxathiins were synthesized for the development of new agrochemical fungicide. Chlorination of trifluoromethylated ${\beta}-keto$ ester 6 followed by the reaction with 1,2-mercaptoethanol gave intermediate 1,4-oxathiane 11. Without purification of 11, substitution of hydroxy group by chlorine, followed by dehydrochlorination of 10 in the presence of triethylamine afforded trifluoromethylated dihydro-1,4-oxathiin ethyl ester 9. Acylation of the hydroxy group of the carboxylic acid 12 followed by treatment of various amines gave the corresponding trifluoromethylated dihydro-1,4-oxathiin carboxamides 5. Antifungal screening (in vivo) of the synthesized compounds against typical plant diseases, which include rice blast, rice sheath blight, cucumber gray mold, tomato late blight, wheat leaf rust, and barley powdery mildew, was carried out. Where meta position of the phenyl group was substituted with isopropoxy or isopropyl group, excellent antifungal activities against rice sheath blight and wheat leaf rust were detected.

• The Korean Journal of Pesticide Science
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• v.7 no.1
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• pp.51-57
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• 2003

For the purpose of a development of new agrochemical fungicides, new compound 4 in which 1,3-thiazoline scaffold as well as urea moiety in the structure was designed through molecular modification of lead compound, 2-imino-1,3-thiazone based on isosterism. The reaction of N-alkylthiourea 5 and bromoacetonitrile in ethanol gave 2,4-diimino-1,3-thiazolidine hydrobromide 6 regioselectively, which was treated with isocyanates gave the corresponding 8 which is tautomer of 4. Antifungal screening (in vivo) of the synthesized compound 8 against typical plant diseases, which include rice blast, rice sheath blight, cucumber gray mold, tomato late blight, wheat leaf rust, and barley powdery mildew, was carried out. Antifungal activities against rice blast of the compound 8 were weaker than those of 2-phenylimino-1,3-thiazoline 1. Some compounds showed weak antifungal activities against wheat leaf rust.