• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.5
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• pp.104-111
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• 2015

This study shows the mechanical properties of alkali-activated slag cement (AASC) synthesized using sulfate with NaOH solution. The used sulfates were calcium sulfate ($CaSO_4$, denoted CS) and sodium sulfate ($Na_2SO_4$, denoted SS). The replacement ratio of sulfates was 2.5, 5.0, 7.5 and 10.0% by weight of slag. NaOH solution of 2M and 4M concentration was used. A sample was activated with sulfate and activated with blended activator (blending NaOH solution with sulfate) respectively. 24 mix ratios were used and the water-binder weight ratio for the test was set 0.5. This research carried out the compressive strength, flexural strength, ultrasonic pulse velocity (UPV), absorption and X-ray diffraction (XRD). In the case of samples with CS, sample with 7.5% CS, sample with 2M NaOH+5.0% CS and sample with 4M NaOH+5.0% CS showed the good performance in the strength development. In the case of samples with SS, sample with 10.0% SS, sample with 2M NaOH+7.5% SS and sample with 4M NaOH+2.5% SS obtained good performance in strength. The results of UPV and water absorption showed a similar tendency to the strength properties. The XRD analysis of samples indicated that the hydration products formed in samples were ettringite, CSH and silicate phases. In this study, it is indicated that when compared to the use of sulfate only, the use of both sulfate and NaOH solution makes mechanical properties of AASC better.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.3
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• pp.47-56
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• 2020

In this study, three levels of W/B(Water to Binder) ratio (0.37, 0.42, 0.47) and substitution ratio of GGBFS (Ground Granulated Blast Furnace Slag) rate (0 %, 30 %, 50 %) were considered to perform RCPT (Rapid Chloride Diffusion Test) at the 1,095 aged day. Accelerated chloride diffusion coefficient and passed charge of each concrete mixture were assessed according to Tang's method and ASTM C 1202, and improving behaviors of durability performance with increasing aged days are analyzed based on the test results of previous aged days from the preceding study. As the age of concrete increases, the passed charge and diffusion coefficient have been significantly reduced, and especially the concrete specimens containing GGBFS showed a significantly more reduction than OPC(Ordinary Portland Cement) concrete specimen by latent hydraulic activity. In the case of OPC concrete's results of passed charge, at the 1,095 days, two of them were still in the "Moderate" class. So, if only OPC is used as the binder of concrete, the resistance performance for chloride attack is weak. In this study, the time-parameters (m) were derived based on the results of the accelerated chloride diffusion coefficient, and the deterministic and probabilistic analysis for service life were performed by assuming the design variable as a probability function. For probabilistic service life analysis, durability failure probabilities were calculated using Monte Carlo Simulation (MCS) to evaluate service life. The service life of probabilistic method were lower than that of deterministic method, since the target value of PDF (Probability of Durability Failure) was set very low at 10 %. If the target value of PDF suitable for the purpose of using structure can be set and proper variability can be considered for each design variable, it is believed that more economical durability design can be made.

• Korean Journal of Breeding Science
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• v.43 no.6
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• pp.606-610
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• 2011

'Jungmo1001' is an early maturing intermediate breeding line developed from a cross between Cheolweon52 and SR14694-57-4-2-1-3-2-2 by the rice breeding team of National Institute of Crop Science, Rural Development Administration (RDA) in 1994. 'Jungmo1001' has about 107 days duration from seeding to heading in mid-northern inland plain, southern alpine area and north-eastern coastal areas. It has about 73 cm in culm length with semi-erect plant type and good canopy architecture. This variety has 13 tillers per hill and 90 spikelets per panicle. Its 1,000 grain-weight of brown rice is 21.2 g which is less than 26.3 g of 'Odaebyeo'. Milled kernels are translucent with non-glutinous endosperm, low amylose content (18.1%) compared with 'Odaebyeo' palatability of cooked rice is very good. This variety shows strong resistance to cold treatment, lodging, premature heading and wilting. This variety shows moderately resistant to blast disease but susceptible to bacterial blight, stripe virus and insect pests. The milled rice yield performance of this variety is about 5.45 MT/ha by ordinary culture in local adaptability test for three years. This variety may be highly adaptable to the mid-northern inland plain, southern alpine area and north-eastern coastal areas of Korea.

• Korean Journal of Breeding Science
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• v.41 no.4
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• pp.547-551
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• 2009

A new commercial rice variety "Chilbo" is a japonica rice (Oryza sativa L.) with resistance to rice stripe virus and high grain quality. It was developed by the rice breeding team of Yeongdeog Substation, NICS, RDA in 2007. This variety was derived from a cross between "Yeongdeog 26" with wind tolerance and lodging resistance and "Koshihikari" with good grain quality. A promising line, YR21324-119-3-2 was selected by a pedigree breeding method and designated as "Yeongdeog 44" in 2004. Regional adaptation yield trials were carried out at eleven locations from 2005 to 2007. As a result, "Yeongdeog 44" was released as a high yielding rice variety with high grain qualilty and virus resistance with the name of "Chilbo". It is short 76cm in culm length and has medium-late growth duration. This variety is resistant to stripe virus and middle resistant to leaf blast disease. It is also tolerant to cold, dried wind. Milled rice kernel of "Chilbo" is translucent, clear in chalkiness. Panel test proved that and it has good eating quality. Head rice ratio of Chilbo is high compared to the check variety, Hwaseongbyeo. Yield potential of "Chilbo" in milled rice is about 5.57MT/ha at ordinary fertilizer level of local adaptability test. This variety would be adaptable to Yeongnam plain, south & east-south coastal, south mid-mountainous, middle plain area of Korean peninsula.

• Korean Journal of Breeding Science
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• v.41 no.4
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• pp.649-653
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• 2009

"Cheongan" is a new japonica rice variety developed from a cross between SR15225-B-22-1-2-1 and Iksan431 in summer season, 1997 by National Institute of Crop Science, RDA. The line SR15225-B-22-1-2-1 has good canopy architecture and multi-disease and insect resistance, and Iksan431 has translucent milled rice and good eating-quality. Heading date of Cheongan is August 13 in central lowland and mid-mountainous areas. "Cheongan" having culm length of 84 cm shows relatively semi-erect pubescent leaf blade and rigid culm, tolerance to lodging with and good canopy architecture. This variety has 14 tillers per hill and 126 spikelets per panicle. It shows tolerance to heading delay and spikelet sterility comparable to Hwaseongbyeo when exposed to cold stress. Leaf senescence of Cheongan progresses slowly during the ripening stage and the viviparous germination ratio was 59 %, similar to that of Hwaseongbyo. "Cheongan" shows moderately resistance to blast disease, but susceptible to stripe virus and brown planthopper. The milled rice of "Cheongan" exhibits translucent, clear non-glutinous endosperm and medium short grain. It shows similar amylose content of 18.7%, gelatinization temperature, and similar palatability of cooked rice compared to Hwaseongbyeo. The milled rice yield of this cultivar is about 5.54 MT/ha at ordinary season culture in local adaptability test for three years. Especially, "Cheongan" has better milling properties of higher 98.4% and 73.9% in the percentage of head rice in milled rice and milling recovery of head rice, respectively, than those of Hwaseongbyeo. "Cheongan" could be adaptable to the central and mid-southern plain area, and mid-western coastal area of Korea.

• Korean Journal of Breeding Science
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• v.40 no.3
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• pp.328-331
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• 2008

Hwangeumnodeul is a new japonica rice cultivar developed from a cross between Milyang165 and HR15151-B-21-3 at Honam Agricultural Research Institute (HARI), NICS, RDA, in 2007. This cultivar has short grains and about 139 days of growth duration from direct seeding to harvesting in the southern plain areas. Culm length of this cultivar is 78 cm and the number of spikelet per panicle is similar to that of the check cultivar, Nampyeongbyeo, while filled grain rate is lower than the check variety. This cultivar is moderately resistant to leaf blast, bacterial blight pathogens of $K_1$, $K_2$ and $K_3$ and stripe virus but susceptible to major virus diseases and insect pests. Milled kernel of Hwanggeumnodeul is translucent with non-glutinous endosperm. This cultivar has about 5.7% and 18.6% of protein and amylose contents, respectively. Palatability of cooked rice of Hwanggeumnodeul is similar to Nampyeongbyeo. Its milling recovery and head rice were 75.6% and 90.0%, respectively. Hwanggeumnodeul yielded 5.69 and 5.61 MT/ha in milled rice at the under wet-direct and dry-direct seeding conditions, respectively which are 17% and 12% higher than the check variety, Juanbyeo. It yielded 5.86 MT/ha, 8% higher than Nampyeongbyeo at the standard fertilizer level of the ordinary transplanting cultivation. "Hwanggeumnodeul" would be adaptable for ordinary transplanting as well as direct seeding in the southern plain including Chungcheong province.

• Korean Journal of Breeding Science
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• v.40 no.3
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• pp.324-327
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• 2008

'Onnuri' is a japonica rice cultivar developed from the cross between 'Milyang 165' and HR14732-B-67-2-3 at Honam Agricultural Research Institute (HARI), NICS, RDA, in 2005. This cultivar has a short grain shape and about 121 days growth duration from transplanting to harvesting in Korean climate condition. In reaction to biotic and abiotic stresses, it shows resistance to blast, bacterial blight pathogen from $K_1$ to $K_3$ and stripe virus, but susceptible to other major diseases and insect pests. The milled kernel of 'Onnuri' is translucent with non-glutinous endosperm. It has about 18.6% of amylose content and better palatability of cooked rice compared with 'Chucheongbyeo' cultivated in Kyunggi province. The milled rice yield of 'Onnuri' is about 5.94 MT/ha under the standard fertilizer level of the ordinary transplanting cultivation. 'Onnuri' would be adaptable to southern plain of Cheonan, middle-northern plain, and southern mid-mountainous of Korea.

• Korean Journal of Breeding Science
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• v.43 no.6
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• pp.549-553
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• 2011

'Jungmo 1012', a new japonica rice intermediate parent developed from a cross between 'Sambaegbyeo' having a good eating-quality and lodging resistance, and 'Ou329', was developed by the rice breeding team of Sangju Substation, National Institute of Crop Science, Rural Development Administration in 2010. This variety has about 120 days growth duration from transplanting to harvesting in southern mid-mountainous area of Korea. It has 78 cm culm length and tolerance to lodging. In reaction to biotic and abiotic stresses, it shows strong resistance to blast and viviparous germination, but is susceptible to bacterial blight, virus diseases, and insect pests. The milled rice of 'Jungmo 1012' exhibit translucent, relatively clear non-glutinous endosperm and medium short grain. It has a little lower amylose content of 18.2%, and higher protein content of 6.3%, and good palatability of cooked rice compared with 'Odaebyeo'. The milled rice yield performance of this variety is about 5.55 MT/ha in local adaptability test for three years. 'Jungmo 1012' will be adaptable to southern mid-mountainous of South Korea.

• Korean Journal of Breeding Science
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• v.43 no.6
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• pp.611-615
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• 2011

'Manjong' is a new japonica rice cultivar developed in 2009 derived from a cross between 'Yeongdeog34' and 'Nampyeongbyeo' at the Department of Functional Crop, NICS, RDA. This cultivar is suitable for the double cropping system after the cash crop cultivation. Heading date of 'Manjong' is later than 'Keumobyeo' under the late transplanting cultivation on July 10. It has high grain fertility under cold conditions and low premature heading. One of the distinguishing characteristics of this variety is its resistance to major diseases like leaf blast and rice stripe virus disease. However, it shows susceptibility to major insect pests and bacterial blight disease. Milled rice kernels are translucent with non-glutinous endosperm and have 7.2% protein and 18.7% amylose contents. Ripening ratio and head rice ratio is very higher than those of 'Keumobyeo'. The palatability of cooked rice is also better than 'Keumobyeo'. The milled rice yield of 'Manjong' in local adaptability tests after harvest of the cash crop is $4.81MT\;ha^{-1}$. This cultivar is suitable for planting in the plain paddy fields of Honam and Yeonnam regions in Korea.

• Korean Journal of Breeding Science
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• v.41 no.2
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• pp.149-153
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• 2009

Junamjosaeng is a new japonica rice cultivar developed in 2006 from a cross between Milyang165*3 and Koshihikari at the Department of Functional Crop Science, NICS, RDA. This cultivar is suitable for the double cropping system (i. e., before and after the cash crop). Heading date of Junamjosaeng is 6 days earlier than Keumobyeo under the late transplanting cultivation on July 10. It has a high grain fertility under cold conditions and low premature heading. One of the distinguishing characteristics of this variety is its resistance to major diseases like leaf blast, bacterial blight races ($K_1$, $K_2$, $K_3$) and rice stripe virus disease. However, it showed susceptibility to major insect pests. Milled rice kernels are translucent with non glutinous endosperm and have 6.7% protein and 19.8% amylose contents. Milling recovery of head rice is 75.7%. The palatability of cooked rice is better than Keumobyeo. The milled rice yield of Junamjosaeng in local adaptability tests after harvest of the cash crop was $4.43\;tons\;ha^{-1}$. This cultivar is suitable for planting in the plain paddy fields of Honam and Yeonnam regions in Korea.