• 소성∙가공
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• 제32권2호
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• pp.53-60
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• 2023

A wide range of grain size was achieved in a Fe-Cr-Mn austenitic stainless steel (STS) by cold rolling and reversion annealing. The tensile characteristics of the STS were analyzed in terms of the dependence of strain induced martensitic (SIM) transformation on the grain size. In the ultrafine grain regime, the steel showed a high yield strength over 1 GPa, a discontinuous yielding, and a prolonged yield point elongation followed by considerable strain hardening. By increasing the grain size, the discontinuous yielding diminished and the yield point elongation decreased. The microstructural examination revealed that these tensile characteristics are closely related to the suppression of SIM transformation with decreasing the grain size. Especially, the prolonged yield point elongation of the ultrafine grained STS was found to be associated with development of unidirectional ε martensite bands. Based on the microstructural examination of the deformed microstructures, the rationalization of the grain size dependence of SIM transformation was suggested.

• 한국작물학회지
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• 제51권1호
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• pp.14-25
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• 2006

Response of grain yield and milled-rice protein content to nitrogen (N) rates at various growth stages is critical for quantifying real-time and real-amount of applied N requirement for target grain yield and protein content. An experiment including 10 N rate treatments at transplanting, tillering and panicle initiation stages with four rice cultivars in 2003, 6 N treatments with two rice cultivars in 2004 and 2005 was conducted. Increase of N rates at PIS significantly increased both grain yield and milled-rice protein content but increase of N rates at tillering stage significantly increased grain yield but not milledrice protein content. Therefore, high grain yield and low milled-rice protein content would be difficult to obtain only by adjusting N rates at PIS. Internal N use efficiency (INUE) was 60.5 kg grain/kg N accumulation on an average over N treatments, cultivars, and experimental years, showing considerable reduction especially at high shoot N accumulation in the experimental year of low sunshine duration. Milled-rice protein content tended to increase almost linearly with increasing shoot N accumulation, but it revealed big variation even at the same shoot N accumulation at harvest. Milled-rice protein content decreased with increasing INUE. N accumulation in the milled rice increased at an almost constant proportion of 45.5 percent of the shoot N accumulated at harvest, showing slight decresing proportion with the increasing shoot N accumulation.

• 한국작물학회지
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• 제29권2호
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• pp.109-113
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• 1984

우리나라 벼 재배품종들의 천립중을 증대시켜 단위면적당 수량능력의 향상을 위한 기초자료를 얻고자 수집된 몇가지 대립종들의 수량성 및 주요특성을 소개하고자 시험한 결과 1. 벼알의 무게와 벼알의 길이, 너비, 두께는 유의한 정(+)의 상관을 보였으며 벼 알의 길이와 모양은 정(+)의 상관(r=0.5707 ${\ast}\;{\ast}$)을 보였다. 2. 우러나라 재배품종의 천립중보다 무거온 14대립종들의 천립중과 수당입수, 주당수수, 등숙비율, 총건물중, 정조중, 수확지수간에는 부(-)의 상관을 보였으나 유의성은 인정되지 않았다. 3. 이들 대립종의 천립중과 생육일수와는 부(-)의 상관을 보였으나 유의성은 인정되지 않았다. 4. 천립중이 상이한 20품종의 천립중과 심복백정도간에는 정(+)의 높은 유의 상관(r =0.8477${\ast}\;{\ast}$)이 인정되었다.

• 한국작물학회지
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• 제44권1호
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• pp.59-63
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• 1999

Yield and growth characteristics were compared for five rice cultivars; a new Tongil-type, so called "super-rice", Dasanbyeo, an old Tongil-type Milyang 23, two japonicas Dongjinbyeo and Ilpumbyeo, and a new plant type (NPT)line IR65600-27-1-2. The objective of this stusy was to clarify the high yielding capacity of Dasanbyeo in terms of growth characteristics. The average grain yield (9 t/ha) of Dasanbyeo was higher than that of Milyang 23 by ca. 9% that of japonicas by 20 to 30%, and that of NPT line by ca. 100%. The higher grain yield of Dasanbyeo was attributable not only to the greater dry matter production but also to the higher harvest index (HI). Dasanbyeo showed the greatest dry matter at harvest owing not only to the rapid leaf expan-sion at early growth stage and the resulting high LAI through the entire growth stage but also to the high NAR despite the high LAI. The rapid leaf expansion of Dasanbyeo at early growth stage seemed to be related in part to the profuse tillering capacity. HI was 0.53 in Dasanbyeo, 0,51 in Milyang 23, 0.41 in japonicas, and 0.35 in NPT line. Dasanbyeo was indebted for its higher HI to the relatively high grain filling ratio in spite of a much greater sink size than the other cultivars. Dasan had a greater source to sink ratio during grain ripening as measured by LAD/spikelet and dry matter production/spikelet which showed positove correlations with the grain ripening ratio. New plant type (NPT) line showed the lowest grain yield owing to the small sink size and the low grain filling ratio which seemed to have resulted from the abundant occurrence of weak-strength spikelets. The weak sink strength, in turn, seemed to have suppressed photosynthesis during the grain ripening stage.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.96-96
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• 2017

Rice is a staple food for nearly half of the world's population, with more than 10,000 rice varieties providing almost one-quarter of the global per capita dietary energy supply. Grain size, panicle size and branch number, grain number in a panicle are directly associated with rice productivity. Recently several genes which increase grain yield were identified through map-based cloning. Gn1a, Cytokinin oxidase, is a major grain number QTL and regulates grain number per panicle. Dep1 increases panicle branching and reduced rachis length. SCM2 (APO1) was identified by a QTL for culm strength and increased spikelet number. OsSPL16 (GW8) controls grain size and shape and then increases 1000-weight of seed. In here, to identify genotype of genes related to yield in 400 of rice germplasms possessed in National Institute of Crop Science, we had first chosen 4 of well-known genes related to yield; Gn1a, Dep1, SCM2, and OsSPL16. Among these germplasms, 195, 382, 165, and 353 of germplasms harbored the dominant type of Gn1a, Dep1, SCM2, and OsSPL16, respectively. We grouped these germplasms into a total of 10 groups using genotypes of Gn1a, Dep1, SCM2 and OsSPL16. Most rice germplasms belong to group 1, harbored Gn1a, dep1, gw8 and APO1, and group 10, harbored gn1a, Dep1, GW8 and apo1. Hanareum2 is the highest productive cultivar in Korea but do not have dominant type OsSPL16, so belong to group 1. On the other hand, in the case of Unkwang, belongs to group 10, which has dominant type of OsSPL16 but do not have the remaining genes. We can grasp the differences in rice germplasms through the Profiling of genes related to these grain yield, which will be useful for cross-breeding to integrate grain yield genes. We are continuously observing the genotype and phenotype of rice that possesses grain yield genes.

• 한국작물학회지
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• 제50권4호
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• pp.262-264
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• 2005

A study on genetic variability and association of yield attributing characters with grain yield was carried out using 35 deepwater rice genotypes. High genotypic co-efficient of variation (GCV) was observed for plot yield, $EBT/m^2$, plant height and days to $50\%$ flowering (DFF). For all the traits, estimates of the phenotypic co-efficient of variation (PCV) were higher than GCV, indicating presence of environmental influence. High heritability and genetic advance was observed for plot yield, $EBT/m^2$ and plant height. Plot yield had significant positive association with test weight, $EBT/m^2$ and DFF. However, test weight had the maximum direct effect on grain yield

• 한국작물학회지
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• 제45권1호
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• pp.14-19
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• 2000

In order to develop an appropriate cultural practice for a newly bred 2-rowed, waxy, naked barley cultivar 'Duwonchapssalbori' in the southern region, 2 varieties, 3 seeding dates, 4 seeding rates were designed with 2 replications. The heading and maturity dates of 'Duwonchapssalbori' were' earlier than 'Saessalbori by 2-5 and 4 days, respectively. Culm length of 'Duwonchapssalbori' was 60 to 66cm with lodging resistance. Grain yields of both varieties were 4.28-4.33 ton/ha in the plot of Oct. 20 seeding, 4.11-4.18 ton in the plot of Oct. 28 seeding, and 3.7-13.89 ton/ha in the Nov. 5 seeding. Grain yield with different seeding rates highly significantly fitted with secondary polynomial equations in the plots of Oct. 20 and Oct. 28 seedings ($R^2$=0.84-0.85), showing the greatest yield with seeding rate of 140kg per ha. However, the grain yield with various seeding rates in the plot of Nov. 5 seeding showed simple linear regression ($R^2$=0.71), showing the seeding rate over 160kg in the case of later seeding to be optimal. Number of spikes per $m^2$ significantly contributed to grain yield, and fitted to simple linear regression ($R^2$=0.881-0.891), suggesting that plenty of early stands should be established at early seedling stage for high grain yield. Young spikes of 'Duwonchapssalbori' in the plot of Oct. 20 seeding elongated with linear increments since Feb. 10 (6.7mm), and showed rapid increment since March 7 (15.1mm). However, elongation of young spikes of 'Saessalbori' began from March 15 with slow increments. From these studies, the optimum seeding date and seeding rate in 'Duwonchapssalbori' were Oct. 20-28 and 140kg per ha for high grain yield in the southern regions.

• 한국물환경학회지
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• 제21권2호
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• pp.169-175
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• 2005

This study was carried out to investigate the effects of irrigation water pollution on the yield and grain quality of rice. It acquires fundamental data to set up water quality standards for irrigation and produce agricultural safety products. The correlations of BOD, T-N, T-P, pH, ECw of the irrigation water with yield, grain appearance quality, and the protein content were evaluated. The field and pot experiments were conducted by using Japonica of Oryza sativa L. during 2 years. BOD concentration in irrigation water effects strongly on grain appearance quality and yield of rice. T-N in irrigation water has strong effect on the yield, appearance, and quality of rice. T-P concentration in irrigation water have not any correlation with yield and quality of rice. pH showed strongly negative correlation with maturity ratio(MTR), 1000 grain weight(TGW), and yield of rice(YLD) as r=-0.803~-0.828(p<0.001) and have no effect on the appearance quality of rice. $EC_w$ indicating salt content showed strongly negative correlation with MTR, TGW, number of grains per panicles(NGP), and number of panicles per unit area(NPM) as r=-0.759~-0.798, and with YLD as -0.753.

• 한국작물학회지
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• 제26권3호
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• pp.219-225
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• 1981

Strong wind of 6.5m/s from electric fan was applied to rice at heading stage to find out the nature of wind damage to panicle. Damaged panicles caused by typhoon were sampled out of field to measure the yield and milling components. Wind-treated glumes were developed into two forms, fertile and sterile, and each of them showed all degree of glume discoloration. The number of fertile grains were higher than sterile grains in a damaged panicle. Averagesdegree of glume discoloration was higher in not flowered glume than in flowered glume. The more recently flowered glumes resulted the higher degree of discoloration among flowered glume. The percent of sterile grain to total number of grains was the highest at stage of just flowering. The glume discoloration representing wind damage at heading state advanced in degree in ten days after treatment compared to that just after treatment. Grain length and grain width were decreased with the increased degree of glume discoloration, while grain thickness was not changed greatly. Chalkiness was a little higher in damaged grain than in normal grain without definite trends by degree of discoloration. Ripening ratio, 1000 grain weight and yield decreased with increased degree of glume discoloration in damaged panicle by typhoon. Decreasing order in yield was white rice, rough rice and brown rice. Ratio of brown rice to rough rice increased, white rice to brown rice decreased, and milling recovery was not changed greatly with increased degree of 히ume discoloration.

• 한국작물학회지
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• 제14권
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• pp.41-45
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• 1973

본 시험은 중부지방에서 담수직파재배에 알맞은 파종립수를 구명함과 파종립수에 EK른 수량 및 수량구성요소의 변이를 알고져 1972년에 수행하였던 바 그 결과를 요약하면 다음과 같다. 1. 최고분얼수는 밀파할수록 직선적으로 증가하여 280립 파종구에서 최고수치를 보였고 그 이후는 점차 감소되었으며 분얼에 대한 경합은 $m_2$당 280립이상 파종구에서 뚜렸했다. 2. 유효경비율은 $m_2$당 120립부터 280립 파종구까지는 파종밀도가 증가될수록 감소되다가 그 이후는 점차 증가되었다. 3. 최고분얼수가 $m_2$당 1,000개 이하에서는 얼자간 경합이 적었다. 4. 수수와 파종립수는 현저한정(+)의 상관이 인정되었고 수수와 일수영화수, 수수와 동숙비율은 (-)의 상관 경향이었다. 5. 수량과 $m_2$당 영화수는 r=0.929이며 수량과 수수는 r=0.695, 수수와 $m_2$당 영화수는 r=0.796이었다. 또한 수량과 수량구성요소간의 순위상관을 보면 수량과 수수가 가장 상관이 높았으며 (r=0.954_ 담수직파에서 수량을 지배하는 요인은 수수이었다. 6. 수량은 $m_2$당 280립 파종구에서 최고를 나타냈다.