• Korean Journal of Soil Science and Fertilizer
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• v.26 no.2
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• pp.85-92
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• 1993

This study was investigated on the morphological characteristics of rice grain as affected by three fertilizer application treatments. Of no-nitrogen, optimum nitrogen, and heavy nitrogen without potassium in three regions of Suweon (Mid-West Plain Zone), Ichon(Mid-Inland Plain Zone), and Kyehwado(South-charyung Mts. Plain Zone) with four varieties, i.e., three Tonsil types(Geumgangbyeo, Milyang 23, and Chilseongbyeo) and one japonica type(Chucheongbyeo, Akibare in Japanese name). The results obtained were as follows: The increase of nitrogen application caused an increase of grain length in rough rice and grain width in milled rice, resulting in a decrease of the width/thickness ratio in milled rice. The width and thickness of rice grain produced in Kyehwado were smaller than those in the other regions. Therefore, the ratio of length/width and length/thickness in rice grain produced in Kyehwado was larger. The one thousand grain weight of rice was heavier at the optimum nitrogen level than at the no-nitrogen and heavy nitrogen without potassium treatment levels. The weight percentage of hull in rough rice grain decreased in accordance with the increase of nitrogen application, while the weight percentage of bran in brown rice was constant. This suggested that for the normal development of rice grain a constant ratio of bran is needed. The morphological change of rice grain by fertilizer treatments and the change of region cultivated could not be distinguished from the native characteristics of the variety. Other grain characteristics were discussed in view of treatment and regional effects.

• Korean Journal of Agricultural and Forest Meteorology
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• v.20 no.1
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• pp.135-143
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• 2018

The effect of elevated temperature on temperate paddy rice will be significant for dependable food supply in East Asia. Using temperature gradient field chamber (TGFC), which was designed to make the horizontal air temperature gradient by $0^{\circ}C$ to $3^{\circ}C$ higher than outside, we examined the measurement to understand the effects of extremely high temperature on paddy rice. In particular, the data of the year 2016, the worst heat wave in over 22 years, was analyzed in this study. The rice height in the relatively warmed condition was rapidly increased during early growth stage. However, the average grain weight and number of spikelet per panicle in the warmed chamber condition were gradually declined with increasing air temperature averaged for 40 days after first heading in each chamber. In particular, the grain yield was more dramatically decreased by the raising temperature because the percent ripened grain was quickly dropped as getting over the threshold temperature for pollination. Therefore, the surplus photosynthetic product by such lower grain filling rate may disturbed the decreases of the NDVI (Normalized Difference Vegetation Index) and SPAD chlorophyll values after first (normal) heading. In addition, the late-emerging head grain were appeared. However, this yield was too small to recover the normal yields decreased by extremely high temperature condition. Our result represented that the warmed condition in 2016 would be the critical limit for the stable yield of temperate paddy rice.

• Tribology and Lubricants
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• v.11 no.5
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• pp.114-121
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• 1995

An ultrasonic technique using normal-incident compressional waves was used to evaluate the surface and subsurface damage in ceramics produced by Hertzian indentation. Damage was produced by a blunt indenter (tungsten carbide ball) in glass-ceramic, green glass and silicon nitride. The damage was classified into two types; (1) Hertzian cone crack, in green glass and fine grain silicon nitride, and (2) distributed subsurface micro fractures, without surface damage, produced in glass ceramic. The ultrasonic technique was successful in detecting cone craks. The measurement results with the Hertzian cone cracks indicated that cracks perpendicular to the surface could be detected by the normal-incident compressional waws. Also shown is the capability of normal-incident compressional waves in detection distributed micro-sized cracks size of subsurface microfractures.

• KIEAE Journal
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• v.7 no.5
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• pp.135-142
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• 2007

This is an experimental study on the structural characteristics of reinforced concrete beams using of the oyster shells as a substitute fine aggregate of concrete. In this study, the main factors consist of the grain sizes and the percentage of substitution of oyster shells to fine aggregate in the equal water cement ratio. The results of the study showed as followed. The initial load value of them represented similar constant within 10% of the maximum load value in each test beam. But the maximum load value and the ultimate load value decreased with increased grain size and the rate of substitution. As the grain size of oyster shells became smaller, the load values of them were somewhat higher. The deflection among deformation properties of reinforced concrete beams with oyster shells represented typical curves like that of normal reinforced concrete. In the deformation of steel and concrete, the deformation was proportionated to the load till yield point and from yield point until approaching the ultimate load point. One type was typical curve of the load and the deformation and the other type irregularly was changed to very small deformation for the load increase centering around load axis. After the analyzing structural behaviors and the properties of reinforced concrete test beams with oyster shells, the most excellent grain size of oyster shells represented 1.0mm and less or 5.0mm and less with taking uniformly, and the percentage of practicable substitution of them to fine aggregate was about 30%.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.345-345
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• 2017

In order to reduce rice cultivation area in paddy fields and to increase domestic self-sufficiency of imported upland grain, it is necessary to increase double cropping area of upland crops in paddy field in accordance with decrease of rice consumption in Korea. The double cropping of spring potato-summer grain maize can be combined because of enough growing season in the southern plain of Korea. Spring potato, which is profitable, can be planted in the late February and harvested in the late May as the main crop. Subsequent grain maize can be planted in early June and harvested in November (maturity in the early October). Spring potato (variety Soomi) yielded $2,544kg\;10a^{-1}$ (tuber) when planted in late February, 2016. When maize was planted in June as the second cropping crop, though growth of plant decreased much, grain yield decreased slightly compared to normal planting in April or May. There was enough time to dry maize ear in the field after maturity before harvesting, which saved labor and time for grain drying, since there is no autumn planting at the double cropping of spring potato-summer grain maize. When grain maize (variety Gwangpyeongok) was planted in the early June (June $10^{th}$), average grain yield of above $860kg\;10a^{-1}$ over 2 years of 2015 and 2016 was obtained, and the annual total yield (potato tuber + maize grain) of 3,400 kg $10a^{-1}$ was obtained. The result indicates that the double cropping of spring potato-summer maize using paddy fields in southern plain of Korea, could contribute to the self-sufficiency of upland crops through the maximum production.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.4
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• pp.274-281
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• 2006

In Korea, rice cultivars have been changing to 'quality' rice rather than high yielding cultivars. However, more than 10% of paddy field has been changed to greenhouse in winter season for cropping of water-melon, oriental-melon, straw berry and et cetra. This experiment has been made to identify the usefulness of critical N and Si fertilization(SF) level to obtain high grain quality rice with reduced insect pest damage by N and SF combination. Before the experiment, watermelon-rice cropping system was maintained for three seasons by farmer from 1998 to 2001. The experiment of N and Si (silicate) fertilization levels was evaluated with Hwayoung-byeo (Oryza sativa L., medium-maturing variety) in 2002 and 2003 in Uiryeong, Korea. Nitrogen fertilization (NF) levels were three and five in 2002 and 2003, respectively, and three SF levels were compared for getting the valuable N/SF level in both years. TOYO-value was positively affected by Si application in N100% plot but it was negatively related with NF level. Normal grain percentage was positively related with TOYO-value and it was highest in 0N plot and Si plots in N100%. Other appearance qualities like powdered, damaged, and cracked grain, were decreased with increasing N fertilization level. SF improved appearance quality in N100% plots but no effects in other treatments. Leaf sheath related diseases were significantly decreased by SF but it was negatively related with NF. In conclusion, SF could be improve grain quality at the same yield levels of conventional fertilization and it also could be reduce the diseases damages of rice plant in all N treatments. NF treatment reduced grain quality and improved grain yield at N50% level, however NF above N50% could not get any kind of benefits. So, compared with conventional fertilizer, reduced NF level is recommended for high grain quality with reduced insect pest damage.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.spc
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• pp.1-8
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• 2008

We carried out this study to analyze changes of rice grain milling properties according to the transplanting time and to identify genetic resources suitable for improving milling quality of rice in paddy field of Yeongnam area. We analyzed grain filling and milling quality of 30 rice varieties. In late transplanting (June 20), heading date was delayed for 6 days, compared to normal transplanting(June 5). The grain filling ratio (GFR), perfect kernel ratio of milled rice (PKR), and head rice recovery (HRR) were improved in late transplanting. There was no significant difference in head rice yield of two transplanting time, even though the milled rice yield in late transplanting was significantly smaller than that in normal transplanting because of the reduction of spikelet numbers per panicle. The uniformity of brown rice grain measured by selection sieve norm was improve in late transplanting. There was no significant difference of milling loss ratio between normal and late transplanting but there was a trend for a increase of milling necessary time in late transplanting. Thus, our result suggest that optimum transplanting time is June 10 to 15 to improve grain filling and milling quality and produce high head rice yield in the southern paddy plain of Yeongnam region. We selected promising 9 rice varieties which are Nampyeongbyeo, Ilmibyeo, Chucheongbyeo, Dongjinbyeo, Hopyeongbyeo, Malguemi, Chilbo, Hinohikari, and Cheongmu having high percentage of ripened grain and milling quality as genetic resources to improve milling characteristics of rice varieties. Chucheongbyeo, Dongjinbyeo, and Malguemi showed the highest grain filling ratio and Nampyeongbyeo had the highest perfect kernel ratio. Nampyeongbyeo and Ilmibyeo showed the highest head rice yield with more than 500 kg/10a.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.6
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• pp.499-504
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• 2001

We evaluated the degree of texture through depth of the superconductor core of Bi-Sr-Ca-Cu-O(BSCCO) superconductor tape. The degree of texture was characterized by pole figure analysis indicating that the degree of texture varied significantly with depth of the superconductor core. It was observed that the degree of texture was higher near the interface than inside the superconductor core. Specifically, as getting near to the center from the sheath/core interface, the orientation of BSCCO became dispersed from normal direction(ND) which, in turn, resulted in the degradation of <001>-fiber texture. In addition, the <001> texture was non-uniform an, better texture was developed along rolling direction(RD), compared to transverse direction(TD). Microstructural investigation showed that grain alignment was locally degraded by the existence of second phases. I was observed that larger grain size and better texturing were developed near the relatively straight interface compared to those inside the superconducting core. Based on our study, the region near the interface is thought to carry significant current compared to that inside the core.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.4
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• pp.316-320
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• 1999

Nine accessions of red rices collected from different regions were tested for germination characteristics in relation to seed maturity and several storage conditions after harvest. No red rice seeds germinated at five days after anthesis (DAA). Wanjuaengmi (long-grain red rice) seeds at 10DAA germinated up to 30% of total samples, producing only abnormal seedlings, whereas 10D-AA-seeds of normal cultivar showed only 3.3% germinability. Some red rice seeds absorbed more water than cultivated varieties, and showed less decrease in germination rate than cultivated varieties when seeds were exposed at -1, -5 or -1$0^{\circ}C$ for up to 60 hours after soaking. Red rice accessions maintained more than 95% germination when stored. indoor for 120 days. Two short-grain red rices showed about 50% germination when overwintered in the field, while other long-grain red rices and cultivated rices germinated less than 10%. Germination of seeds overwintered in clay loam soil was lower than that in loam soil, and seeds on surface germinated less than those in 1~7cm depth.

• Plant Breeding and Biotechnology
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• v.6 no.4
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• pp.363-380
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• 2018

Wheat is frequently exposed to high temperature during anthesis and ripening period, which resulted in yield loss and detrimental end-use-quality. The transcriptome analysis of wheat under high temperature stress during the early stage of the grain filling period was undertaken. Three expression patterns of differentially expressed genes (DEGs) during grain filling period were identified. The DEGs of seed storage protein and starch-branching enzyme showed continuous increases in their expressions during high temperature stress, as well as during the recovery period. The activities of the enzymes responsible for the elimination of antioxidants were significantly affected by exposure to high temperature stress. Only the WAS-2 family genes showed increased transcription levels under high temperature stress in dehulled spikelets. The relative transcription levels for sub-genome specific WAS-2 genes suggested that WAS-2 genes reacted with over-expression under high temperature stress and decreased back to normal expression during recovery. We propose the role of WAS-2 as a protective mechanism during the stage of grain development under high temperature in spikelets.