• Journal of the Korean Society for Heat Treatment
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• v.35 no.4
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• pp.211-219
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• 2022

It is known that superplastic materials with ultrafine grains have high elongation mainly due to grain boundary sliding. Therefore, in the present study we examined the influence of grain refinement, caused by a repetitive cold rolling and annealing process, on both superplastic elongation and superplastic deformation mechanism. The cold rolling and annealing process was repetitively applied up to 4 times using Fe-10Mn-3.5Si alloy. High-temperature tensile tests were conducted at 763 K with an initial strain rate of 1 × 10^-3 s^-1 using the specimens. The superplastic elongation increased with the number of the repetitive cold rolling and annealing process; in particular, the 4 cycled specimen exhibited the highest elongation of 372%. The primary deformation mechanism of all specimens was grain boundary sliding between recrystallized α-ferrite and reverted γ-austenite grains. The main reason for the increase in elongation with the number of the repetitive cold rolling and annealing process was the increase in fractions of fine recrystallized α-ferrite and reverted γ-austenite grains, which undergo grain boundary sliding.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.30 no.1
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• pp.39-46
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• 1985

Heading time was hastened by the combination of seeding time and longday treatment in order to elucidate the effect of early heading on earliness in maturity, vegetative growth and grain yield in five barley varieties and four wheat varieties under field conditions in Suwon, Korea, 1978-79. About 15 days of earliness in heading accelerated only 2 to 6 days in maturity. Furthermore, the duration of grain fill was not much prolonged comparing with the extension of days from heading to maturity, because of the extension of periods from heading to anthesis at lower temperature resulting in somewhat greater final grain weight. Periods from heading to anthesis and from anthesis to maturity were negatively correlated with the air temperature. In early heading, leaf area at 10 days after anthesis and net assimilation rate were much limited, and although leaf area duration got larger, presumably, it could not make up for the reduction of grain yield. Grain yield per plant reduced noticeably in early heading. This was mainly caused by the reduction of spike number and grain number per spike.

• Korean Journal of Plant Resources
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• v.15 no.1
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• pp.62-66
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• 2002

To investigate the critical seeding date for Daeyeupdlkkae in the middle area of Korea, we seeded from 30 April to 20 July with 20-day intervals on the experimental field in Chungbuk-Do agricultural research and extension service. As seeding date was delayed, days to emergence were shortened, flowering and maturing date were delayed, but maturing period was not significantly affected by seeding date. Delayed seed date resulted in decreased stem length, culm diameter, number of branches per plant and number of nodes on the main stem. Cluster length and 1,000 grain weight increased but number of cluster per plant and number of seed capsules per cluster decreased with delayed seeding. Seeding date up to 10 June showed no effected on grain yield, but 30 June and 20 July decreased 10% and 38%, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.24 no.3
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• pp.13-20
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• 1979

The use of liming material raised soil pH. This brought about a decrease in panicle number per hill. but an increase in the number of grains per panicle in pot cultured paddy production. It also improved grain maturity and thousand grain weight. .An effective control of such contradictory effect of liming material would be one way to increase the paddy production in actual field.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 1998.10b
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• pp.10-10
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• 1998

The growth process of solid grains in a liquid matrix is usually explained in tem1S of Ostwald ripening. The variation of growth (dissolution) rate as a function of grain size during Ostwald ripening predicted that the dissolution rate becomes very large as grain size decreases but the growth rate of a large grain is rather limited. Therefore. a rather uniform size distribution of grain size is maintained once after the quasi-equilibrium state is reached. Quite frequently, however, the exaggerated grain growth (EGG) is observed to occur: only a limited number of grains grow exceptionally. From the observation that the EGG occurs only for the faceted grains with apparently straight solid-liquid interfaces, the EGG is suggested to be the consequence of growth process controlled by 2-dimensional nucleation. In this study, the result by computer calculation on the grain growth process controlled by various mechanisms will be given.

• Journal of Powder Materials
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• v.10 no.1
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• pp.57-62
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• 2003

The effect of bedding on the microstructure of $Si_3N_4$ added with ultra-fine SiC was investigated. The bedding and the addition of ultra-fine SiC effectively inhibited grain growth of $Si_3N_4$ matrix grain. The microstructures of the specimens sintered with bedding powder consisted of fine-grains as compared with the specimens sintered without bedding powder. In addition, the grain size and the difference of grain size between the specimens sintered with bedding and without bedding was reduced with increasing SiC content. Some ultra-fine SiC particles were trapped in the $Si_3N_4$ grains growed. The number of SiC particles trapped in the $Si_3N_4$ grains increased with increasing the grain growth. When ultra-fine SiC particles were added in the $Si_3N_4$ ceramics, the strength was improved but the toughness was decreased, which was considered to be resulted from the decrease of the grain size.

• Journal of the Korean Society of Visualization
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• v.6 no.2
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• pp.20-27
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• 2008

The color sorting technique utilizing the image processing method is very applicable tool to analyze motion of a free-falling object in many agricultural and industrial research fields. In the present study, we have developed an image processing system and algorithm to sort good quality rice grains effectively from the bad ones. The system employs a high speed rate line-scan CCD camera with 2K-pixels and worked with a high speed DSP and FPGA in-line. It can accumulate acquired line-scan image data and visualize each grain image clearly. As a result, we can easily calculate the number of pixels occupied by grain(=grain size), gray level and its correct position by visualizing grain images rapidly.

• Journal of Korea Foundry Society
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• v.3 no.3
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• pp.167-173
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• 1983

The effect of sand grain size on the various properties of mold is not only basic but important interest which we have to deal with.And the relation among the various properties of mold (strength, permeability, flowability, compactability, hardness, deformation, toughness etc.) is very complicated and inaccurate, so we can delineate the behavior of mixture (sand+water+bentonite) with experience only. Within recent years a so-called rigid-water theory has been accepted as a means of advancing logical explanations for the research aimed at delineating sand-clay-water relationships. By changing grain size or mesh no. of grain, specimens have been subjected to green compressive strength, permeability, deformation, flowability, compactablity, toughness at room temperature. Under constant mulling energy and ratio of water/bentonite, the results obtained were as follows: 1. With decreasing grain size green compressive strength of the specimen increased. 2. With decreasing grain size permeability decreased. 3. With decreasing grain size flowability and bulk density decreased but compactability increased. 4. With decreasing grain size deformation decreased but toughness increased. 5. At 60 mesh no., the properties of specimen are conspicuously changed. The reason is that the total surface area of sand grain which affects the type of bonding between sand grains is more changed at 60 mesh number.

• Journal of Life Science
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• v.13 no.1
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• pp.29-33
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• 2003

The study was conducted to get genetic information on quantitative characters of $F_1$ in barley through diallel crosses using seven malting barley. The results obtained were summarized as follows. Additive, dominant, maternal, and reciprocal effort were observed in culm length, spike length, awn length, culm diameter, grain length, grain width, ]lumber of grains per spike, and 1000 grain weight. Based on the Vr-Wr graphical analysis, culm length, spike length, awn length, grain length, and number of grains per spike were found to be inherited over dominance. Dominant effects were higher than additive effects in culm length, spike length, awn length, culm diameter, grain length, grain width, number of grains per spike, and 1000 grain weight. The narrow- sense heritability showed high value as 40.06% for spike length.

• Korean Journal of Community Nutrition
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• v.6 no.1
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• pp.3-15
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• 2001

To assess diet quality by food group intake and to investigate the interrelationship of age, dietary diversity score(DDS), dietary variety score(DVS), dietary frequency score(DFS), food group intake and nutrient intake with food group intake, a dietary survey was conducted with 176 preschool children aged 1 to 6 in Busan using a 24-hr recall method. Food group intake was assessed by food number consumed and intake frequency by six food groups(grain, meat, vegetable, fruit, dairy, sweets group). The mean food numbers consumed and intake frequencies by six feed group were 3.1 and 4.0 in the grain group, 3.6 and 4.0 in the meat group, 3.5 and 4.1 in the vegetable group, 1.0 and 1.1 in the fruit group, 1.3 and 1.5 in the dairy group, 1.4 and 1.4 in the sweets group respectively. As age increased, the intake frequency of the grain group(p<0.05) increased but that of the dairy group(p<0.05) decreased significantly. The DVS and DFS didn't show significant correlations with intake frequency of the dairy group. The grain group intake had significant positive correlations with intakes of the meat, vegetable, and fruit groups. The vegetable group intake had signigicant positive correlations with intakes of the grain and meat groups. The dairy group intake had significant positive correlation with sweets group intake but negative correlations with intakes of the grain and vegetable groups. As the intake frequency of the meat group increased, the NAR(nutrient adequacy ratios) of all nutrients and NAR(mean adequacy ratio) increased significantly. NARs of provein iron, vitamin B$_1$, niacin had the highest correlation with the meat group intake and those of protein, calcium, phosphorous, and vitamin B$_2$ had the highest correlation with the dairy group intake. NARs of vitamin A and vitamin C had the highest correlation with intake of the vegetable and fruit groups respectively. Children with food number consumed and intake frequency of above 6 and 4 in the grain group or above 6 and 6 in the meat group or above 4 and 8 on the