• Research in Plant Disease
• /
• v.19 no.3
• /
• pp.216-219
• /
• 2013

A total of 75 soybean cultivars developed in Korea was screened against soybean cyst nematode (SCN), Heterodera glycines HG type 2.5. Cysts developed on soybean cultivars ranged from 104 to 624 cysts per pot. There was no resistant cultivar but 'Jangyeopkong', 'Saealkong', 'Miryangkong', and 'Mansukong' were moderately resistant; 33 cultivars were moderately susceptible and the other cultivars were susceptible. 'Jangyeopkong', 'Saealkong', 'Miryangkong', and 'Mansukong' could be recommended for soybean fields infested with SCN until developing SCN resistant soybean.

• Korean journal of applied entomology
• /
• v.32 no.3
• /
• pp.348-353
• /
• 1993

The fluctuation of insecticide resistance in the green peach aphid (GPA) in fields was investigated by caboxy1 esterase (CE) activity index analysis. Of the GP A Populations occurred on the red pepper seedlings, aphids in the untreaLed and treaLed with acephate plots showed 40 and 78 resistance percent (RP), respectively. Aphids in the untreated kale field showed the RP value 24 in July, contrast to 83 in October. Mean RPs of aphids from 18 localities were 50 + 14 in summer and B2+ 10 in late fall, indicating a seasonal fluctuation of Lhe CE activity.

• Journal of Plant Biotechnology
• /
• v.32 no.4
• /
• pp.243-250
• /
• 2005

The coat protein gene (AF296280) of the Korean isolate Potato leafroll virus (PLRV) was cloned and the open reading frame (627 bp) was transformed into potato (Solanum tuberosum cv. Superior). Out of seventeen individual transgenic lines, five lines were identified to confer resistance to PLRV through the five generation's selection program in the greenhouse as well as isolated trial field. Successful introduction and genetic stability of coat protein gene in the genome of potato were confirmed by polymerase chain reaction (PCR), Southern blot hybridization and northern blot hybridization. Some of the transgenic lines were highly resistant to PLRV but did not show any resistance to less homologous Potato virus Y (PVY). Our results suggest that the resistance to PLRV is due to homology dependent gene silencing by sense strand coat protein gene. In addition, the results of field test through five generations showed that there were no significant differences comparing to nontransgenic potatoes in the morphological aspect of shoot as well as tuber, Ho remarkable differences were also observed in the major agronomic characters and yields except for the resistance to PLRV.

• 한국도로학회:학술대회논문집
• /
• 2009.11a
• /
• pp.139-143
• /
• 2009

• International Journal of Highway Engineering
• /
• v.13 no.1
• /
• pp.139-148
• /
• 2011

Asphalt concrete overlay method is used by general maintenance and rehabilitation of construction for aged concrete pavement in Korea. However, in case of the AC overlay method to extend service life of the existing concrete pavements, various distresses of reflection crack, pothole and rutting are the typical problems of the asphalt overlay on existing concrete pavement since it has different physical characteristics between asphalt overlay and existing concrete pavement. To achieve this, application of concrete overlay method is required instead of AC overlay method. Concrete overlay method has advantages that can reduce maintenance cycle and costs since it has excellent bearing value for heavy vehicles and no rutting. However, technical problems of detour road construction, traffic control and other disadvantages happened by long curing time. Thus, in this study and experimental research were launched to evaluate the workability, durability and resistance against environmental loading of Very Rapid Hardening Acrylic Polymer Modified Concrete(VRH-APMC) for application of bonded concrete overlay method. Test results showed that the compressive and bond strength were exceed 21MPa and 1.4MPa of target strength after four hours for rapid traffic opening properties. And tests of resistance against environmental loading results showed that VRH-APMC secured excellent durability. Thus, it was known that VRH-APMC was suitable material for large scale bonded concrete overlay method, and it was possible to use maintenance and rehabilitation method which needs enough workability and rapid traffic opening.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.39 no.4
• /
• pp.523-530
• /
• 2019

Pavement distress and traffic accidents are caused by pot-hole. In addition, direct and indirect damages of road users are increasing, such as loss of life due to personal injury and damage to vehicles. Generally, the asphalt concrete pavements are continuously aging from the production process to the terminal performance period. Aging causes stripping due to cracks and moisture penetration and weakening the pavement structure to induce pot-hole. In this study, adhesion performance and moisture sensitivity were evaluated according to aging degree in order to investigate the effect of aging on asphalt pavement. As a result of the study, the viscosity of the asphalt binder was increased with aging and the bond strength of the aged was increased 2~3 times than that of the unaged. The results of accelerated aging test showed an increases in indirect tensile strength and the increase in the TSR (Tensile Strength Ratio) by 4.2~8.9 %. As a result, it is noted that the anti-stripping and adhesion performances of the aged asphalt concrete are improved compared to the unaged one under the aging conditions of asphalt binder coated on aggregates.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.29 no.2D
• /
• pp.209-216
• /
• 2009

This study was conducted to develop a thin paving technique using polymer epoxy resin materials which is considered as a durable pavement materials. The mechanical performance characteristics of the polymer epoxy resin materials were also evaluated to confirm the validity as a pavement materials. To estimate the performance properties of the materials, bending tests and bonding tests were performed using freeze-thaw and ultra-violet rays to accelerate the aging of materials. In addition, HYUNStay, a commercial structural analysis program for cable-stayed bridges, was used to compare the effect of paving materials between the polymer epoxy resin materials and the conventional ones on the reduction of cable tension and on the stability of the main tower. According to the test results, it is noted that the thin paving technique using polymer epoxy resin materials can improve the performance and durability of pavement compared to the conventional one.

• Korean journal of applied entomology
• /
• v.13 no.2 s.19
• /
• pp.83-88
• /
• 1974

Several selected rice varieties Tong-il (Suweon #213-1), Jinheung, IR747, Suweon #229 and so forth were evaluated for their resistance to the striped rice borer, Cltilo suppressalis Walker. The resistance appears to be non-preference and antibiosis in nature. Under laboratory and greenhouse conditions, resistance to striped rice borer was manifested by the low larval weight, percentage of pupation and number of eggs recorded. In the cage test, varieties Suweon #240 and Shenshuraku appeared to be non-preferred by the borer moths for oviposition. Under field condition, variety Tetep received the lowest percentage of infested tillers.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.25 no.2
• /
• pp.58-65
• /
• 2021

As increasing social needs of pavement maintenance, pattern frame method has been constructed in Korea. The pattern frame not only increases the skid resistance of pavements but also improve the scenery. However, construction of the pattern frame currently relies on imported materials. In this paper, we localize the materials used in pattern frame and conduct performance verification on them. The important performance indicators are the adhesion strength of undercoating materials and the skid resistance of finished pattern frames. The adhesion strength was targeted at 1.4MPa, and the localization alternative material met the target performance with 2.35MPa, the skid resistance performance was targeted at 40BPN, and the localization alternative material met the target performance with 75BPN. In the case of localized materials, approximately 40% cost reduction (per 1m²)compared to imported materials was confirmed.

• Resources Recycling
• /
• v.19 no.6
• /
• pp.36-42
• /
• 2010

Researches on resources recycling in the field of construction have made an extensive progress such as recycled aggregate of waste concrete and recycling of asphalt. On the other hand, there are almost never researches on pavement method with used waste frying oil. In South Korea, 0.2 million ton used waste frying oil is discharged every year. It is guessed that about 0.1 million ton used waste frying oil can be collected. If used waste frying oil is recycled, it is expected that disuse cost will be reduced and water pollution of rivers will be prevented. Therefore, the purpose of the study was to evaluate on mechanical features (strength, water resistance, chemical resistance, abrasion resistance, freezing and thawing resistance and permeable coefficient) whether dense graded permeable concrete mixing silica sand with flexible alkyd resin manufactured by making ester reaction with collected used waste frying oil to make alkyd resin could be applied to road pavement for non-roadway. The results of the study were as follows. In flexural strength, it had 1.6 times as much as road design standard 4.5MPa. In water resistance, chemistry resistance and freezing and thawing resistance, they had lack of strength in early age. As age went by, they didn't have large changes. And curing temperature had phenomenon of increase in strength at rather low temperature than high temperature by glass transition temperature of resin. Therefore, considering workability, strength and durability when it was applied to road pavement, it was reasonable that the mixing ratio of flexible alkyd resin was 10~15% in comparison with silica sand weight.