We investigated the effect of diameter and content of carbon nanotubes (CNTs) on the physical properties of styrenebutadiene rubber (SBR)/CNTs nanocomposites. CNTs-reinforced SBR nanocomposites were prepared by the melt mixing process. CNTs with different diameters were synthesized by the chemical vapor deposition method (CVD). In this work, the mechanical property and other physical properties of SBR/CNTS nanocomposites were discussed as a function of the content and diameter of CNTs.

Chop molding composites and 2D carbon/carbon composites were manufactured by hot press molding method. Phenol resin of novolac type was used for matrix precursor and PAN-based carbon, PAN-based graphite and pitch-based carbon fiber were used for reinforcement and boron oxide was used for oxidation retardant. All of the composites were treated by 2000℃ and 2400℃ graphitization process, respectively. After graphitization process, amount of a boron residue in carbon/carbon composites is much according to irregularity of used raw materials. Under the presence of boron in carbon/carbon composites, catalytic effect of boron was a little at 2000℃ graphitization temperature. However, it was quite at 2400℃ graphitization.

미국의 원전해체 지침서인 MARSSIM과 MARLAP에서는 의사결정 전 부지조사를 계획하고, 계획한 조사를 시행하는데 Data Life Cycle의 사용을 권장하고 있다. 부지조사 계획단계에서 설정되는 데이터품질목표(DQO)는 부지조사 수행 및 설계의 모든 측면에서 얻을 수 있는 데이터를 최선으로 활용하는 방법을 제시하고, 부지조사 계획을 체계화하여 공식적으로 중요한 의사결정을 내리는데 필요한 정보를 얻을 수 있도록 한다. DQO의 일곱 과정 중 5~7단계에서는 앞선 단계에서 수집한 정보를 이용하여 합리적이고 신뢰성있는 의사결정을 내릴 수 있도록 부지조사를 설계하는 과정이다. 이 과정 중 설정되는 회색영역은 관심핵종에 대한 조사단위의 평균농도가 실제로 DCGL을 초과하지 않음에도 불구하고, 초과한다고 판단하여 제염활동과 같은 추가적인 활동을 하도록 결정내리는 Type II 의사결정 오류로 인한 결과가 미약할 것으로 생각되는 농도범위로 정의된다. 회색영역은 부지에서 수집한 Sample에 속한 특정 핵종의 평균농도와, 규제한도로서 설정될 수 있는 잔류방사능 유도농도(DCGL)를 이용하여 정할 수 있다. 회색영역을 설정함으로써 가장 자원효율적으로 부지조사계획을 설정할 수 있으며 의사결정 오류에 대한 영향을 최소화 할 수 있다. 선행연구로 도출된 고리 1호기의 DCGL을 이용하여 회색영역을 설정하고, 이를 이용해 올바른 의사결정을 내릴 수 있도록 하는 Sample의 농도평가 방법을 제시하였다.

Grain weight is the most important target not only as a major component of grain yield, but also of the cooking qualities in rice breeding program. In a previous study, a high-resolution physical map targeting a cluster of yield-related QTLs for grain weight, spikelets per panicle has been constructed using series of BC3F4 nearly isogenic lines (NILs) derived from a cross between the Korean japonica cultivar Hwaseong and O. rufipogon. The QTLs including grain weight trait have been mapped in a 25.5kb region containing three genes. Based on GenBank database, these genes include male sterility 5 (OsMs5, LOC_Os09g36740), similar ascorbate peroxidase (OsApx, LOC_Os09g36750) and glutelin family protein (OsGlu, LOC_Os09g36760). Their endogenous expression patterns were analyzed in various rice tissues (2-week seedling, flag leaf, root and panicle) from the parental lines, Hwaseong and NIL-gw9. Semi-quantitative RT-PCR and qRT-PCR were performed using gene specific primer sets. The cDNAs of the similar OsApx gene of Hwaweong and NIL-gw9 were cloned. Over-expression and RNAi knock-down transgenic plants using three genes are under construction for the functional characterization of the genes. The results will be discussed.

Drought stress is one of the major stresses affecting growth and productivity in rice. Drought tolerance is a complex trait governed by quantitative trait loci(QTLs) making it difficult to understand mechanisms underlying it. We generated a set of 55 introgression lines via backcrosses using Milyang23, the Korean Tongil-type rice variety as the recurrent parent and Oryza glaberrima (IRGC Acc. No. 103544) as a donor parent. 139 SSR markers were used to genotype 55 introgression lines. The 55 introgression lines with Milyang23 were evaluated for physiological traits such as fresh shoot weight (FSW), fresh root weight (FRW) and dry shoot weight (DSW) under the control and 30% PEG-treated condition. Three lines (IL9, IL12, and IL55) showing significant difference with Milyang23 were selected for further analysis. Genotyping revealed that three lines had four, four and two O. glaberrima homozygous segments, respectively. IL9 performed better than Milyang23 in all traits measured in the 30% PEG-treated condition. IL9 possessed four O. glaberrima introgressions on chromosomes 1, 2, 6 and 7. IL12 performed better than Milyang23 in FSW and FRW and contains four O. glaberrima introgressions on chromosomes 3 and 6. IL55 contains two O. glaberrima introgressions on chromosomes 2 and 6. Three lines shared the O. glaberrima segment delimited by markers RM133-RM225 at chromosomes 6. This region corresponds to the QTL region for drought tolerance reported by other previous studies. Although IL9 and IL12 showed improved drought tolerance at the seedling and vegetative stage, they performed poor under the drought stress at the reproductive stage implying that the level of drought tolerance differs according to the growth stage in rice. IL55 was not significantly different from Milyang 23 in SPP and FER and had significantly higher no. of the total grain than Milyang 23. This result seems to indicate that IL55 will be a good resource for drought tolerance breeding. The population would be useful not only in developing drought tolerant lines in the breeding program but also in fine-mapping the genes/QTLs for drought tolerance.

Rice mesocotyl is the region between the coleoptile node and point of union of the culm with the root. The mesocotyl is one of the important factor contributing to rice seedling emergence from soil in direct seedling. Several quantitative trait loci (QTLs) for mesocotyl elongation of rice had been reported in few studies. However, association mapping of mesocotyl elongation QTL was not conducted. For that reason, we detected QTLs for mesocotyl elongation in agar and soil conditions and confirmed the potentials of QTLs using chromosome substitution lines (CSSLs). Backcross inbred line (BILs) and chromosome segment substitution lines (CSSLs) derived from a cross between Kasalath and Nipponbare were employed to detect QTLs for mesocotyl elongation in rice. A total of 12 QTLs for mesocotyl elongation were detected on chromosome 1, 3, 6, 7, 9 and 12 using 98 BILs in agar and soil conditions. Two QTLs, qMel-1 and qMel-3 were consistently detected in both conditions. For substitution mapping of qMel-1 and qMel-3, across was made between 2 CSSLs, CSSL-6 and CSSL-15. Our results showed that the qMel-1 was located between two markers RM5448 and RM5310 on chromosome1 and the qMel-3 was located between RM15859-RM15974 on chromosome3. To understand factors controlling mesocotyl elongation, cell expansion and division of rice mesocotyl were investigated. Moreover, microarray analysis was conducted to select candidate genes using near-isogenic lines for two QTLs. 194 genes were up- and down regulated in rice mesocotyl.

Drought stress is one of the major stress affecting growth and productivity in rice. Drought tolerance is a complex trait governed by quantitative trait loci (QTLs) making it difficult to understand mechanisms underlying it. We generated a set of 55 introgression lines via a backcrossing using Milyang23, a Korean Tongil-type rice variety as the recurrent parent and O. glaberrima (IRGC Acc. No. 103544), an exotic collection from Mali, West Africa as donor parent. 141 SSR markers were used to genotype 55 introgression lines. The 55 introgression lines with the Milyang23 were evaluated for physiological traits such as Fresh shoot weight (FSW), Fresh root weight (FRW) and Dry shoot weight (DSW) under control and 20% PEG-treated condition. Three lines (IL9, 12, 55) showing significant difference with Milyang23 were selected. The genetic background of the three lines were similar to Milyang23 and it has four, four and two O. glaberrima homozygous segments, respectively. IL9 performed better than Milyang23 in all traits measured in the 20% PEG-treated condition. IL9 possessed four O. glaberrima introgressions on chromosomes 1, 2, 6 and 7. IL12 performed better than Milyang23 in FSW and FRW. IL12 contains four O. glaberrima introgressions on chromosomes 3 and 6. And IL55 contains two O. glaberrima introgressions on chromosomes 2 and 6. O. glaberrima segment delimited by markers OSR19-RM225 at chromosomes 6 was commonly present in these three lines. This region corresponds to the QTL region for drought tolerance reported by other previous studies. A set of introgression lines are being developed containing only few chromosomal segments from O. glaberrima in the Milyang23 background. These would be useful not only in developing drought tolerant lines in the breeding program but also in fine-mapping the genes/QTLs for drought resistance.

Using a series of BC8F4 nearly isogenic lines(IL-20) derived from a cross between Hwaseongbyeo, as the recurrent parent, and wild rice Oryza minuta (IRGC Acc. No. 101144) as the donor parent we constructed a high-resolution physical map for the days to heading (dth9)-QTL. dth9 QTL was mapped to the long arm of chromosome 9 across a 34.74-kb region containing 8 predicted genes. Heading date of Japonica rice variety Hwaseongbyeo was one week earlier than a near-isogenic line (NILs) IL-20 under natural field (NF) conditions and 3-4 days under short-day (SD) conditions implying that the dth9-QTL is involved in photoperiod sensitivity in rice. Of the 8 predicted genes three were protein-coding genes in dth9-QTL region. According to RiceXpro published data, micro-array analysis of different leaf developmental stages of Nipponbare showed a higher level of LOC_Os09g36700 mRNA expression during panicle initiation stage. This data further supported our prediction that dth9 locus is responsible for delayed heading in IL-20. Previous studies showed that RNase T2 family proteins are involved in photoperiod sensitivity. Based on these findings we sequenced two candidate genes, which encoded for RNase T2 family proteins. Interestingly, we found the existence of a missense mutation in LOC_Os09g36700 gene suggesting that dth9-QTL might control difference in days to heading between Hwaseongbyeo and IL-20. The QTL for days to heading had not been detected in previous QTL studies between Oryza cultivars, indicating the existence of potentially novel allele from O. mimuta.

In this study, we estimate the interannual spatial and temporal distributions of fishing grounds at night in the East Sea based on satellite and in-situ data. We observe that the 15℃ thermal front moves in the north-south direction according to the movement of the warm water (above 18℃) in the Tsushima Warm Current (TWC) area, forcing the cold water area (below 10℃) to either expand or shrink. The interannual variations of sea surface temperature (SST) in winter represented by the indicator SST of 6℃ are consistent with the east-west zonal areas in the central East Sea which represented over 1℃ standard deviation of SST in February during 1990-2000. Annual SST in the fishing grounds of common squid fishing vessels, observed both by fishing vessels and satellites range from 9-22℃, with the satellite-observed data having a larger range than the fishing vessel-based ones. The interannual distributions of the common squid fishing grounds in the East Sea are mostly concentrated in the TWC area in the southwestern part of the East Sea and in the coast of southern Honshu and Hokkaido in Japan. The interannual distributions of the nighttime fishing vessels are consistent with the catches investigated from the fishing vessel.

High grain yield is one of the most important traits for improvement in rice breeding program. Much attention has been given to the genetic bases of spikelets per panicle (SPP) and grain weight (GW) because of their imporftance in rice yield. In this study, IL28, near isogenic line (NIL) developed by introgressing chromosomal segments from Moroberekan into Ilpumbyeo, showed significant increase in number of spikelets per panicle and 1,000 grain weight compare to the recurrent parent Ilpumbyeo. Quantitative trait locus (QTL) analysis in 1150 F2 plants derived from a cross between IL28 and Ilpumbyeo, indicated that both qspp6 and qgw6 were located in the interval RM3430 – RM20580. To map the QTL more precisely, substitution mapping of qspp6 and qgw6 using F4 lines was conducted. As a result of substitution mapping with fifty F4 lines, qspp6 was mapped to an 429kb interval between RM20521 and RM20562 while qgw6 was mapped to a 267kb interval between RM20562 and RM20572 based on the japonica genome sequence. This result seems to indicate that qspp6 and qgw6 are two different genes. It is notable that these QTL, qspp6 and qgw6 are independence from undesirable height and flowering time. Moreover, there was no negative correlation between qspp6 and qgw6 when two genes are pyramided in the genetic background of Ilpumbyeo. SSR markers tightly linked to the qspp6 and qgw6 will facilitate cloning of the gene underlying these QTLs as well as marker assisted selection for variation in SPP and TGW in an applied breeding program.

The Brown planthopper (Bph) is one of the most serious pests of rice affecting rice yield and quality throughout the country. Combining the Bph resistance in the existing quality japonica cultivars is an important breeding target in Korea. Wide crosses using several strains of AA-genome wild rices, O.rufipogon have been used to produce the primary germplasm which is highly resistant to Bph. By repeated backcrossing, the resistance gene was introgressed in the background of two japonica cultivars, Ilpum and Hwaseong. Among the advanced backcross progenies, the ten BC2F3 lines were identified as the highest resistance in the comparative Bph bioassay with other resistant sources. The 24 polymorphic markers spanning the twelve chromosomes were tested for association with marker genotypes and resistance/susceptibility reaction in the 80 BC2F3 lines, RM3748 on the chromosome 7 showed the highest association.

In previous studies, we reported that a QTL for 1000-grain weight (TGW), qTGW3 was located in the interval between RM60 and RM523 (1.2Mb) on chromosome 3 using advanced backcross lines derived from a cross between Oryza sativa ssp. Indica cv. Milyang 23 and O. glaberrima. The O. glaberrima alleles at this locus increased TGW and GL in the Milyang 23 background. To further confirm and narrow down the position of the QTLs on chromosome 3, twenty lines with different O. glaberrima segments in the target region were selected. Twenty lines were evaluated for seven agronomic traits including 1,000 grain weight and grain length and also genotyped with ten SSR markers. Sixteen lines(A, B, C groups) with the O. glaberrima segment flanked by SSR markers, RM60 and RM7332 displayed significantly higher values than Milyang 23 in TGW and GL whereas four lines(D, E groups) without the O. glaberrima segment displayed no difference in TGW and GL. The result indicates that two QTL, qTGW3 and qGL3 are located near RM60 and RM7332.