• Korean Journal of Materials Research
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• v.30 no.12
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• pp.672-677
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• 2020

Expensive PCBN or ceramic cutting tools are used for the processing of difficult-to-cut materials such as Ti and Ni alloy materials. These tools have a problem of breaking easily due to their high hardness but low fracture toughness. To solve this problem, cutting tools that form various coating layers are used in low-cost WC-Co hard material tools, and researches on various tool materials are being conducted. In this study, WC-5, 10, and 15 wt%Ni hard materials for difficult-to-cut cutting materials are densified using horizontal ball milled WC-Ni powders and pulsed current activated sintering method (PCAS method). Each PCASed WC-Ni hard materials are almost completely dense, with a relative density of up to 99.7 ~ 99.9 %, after the simultaneous application of pressure of 60 MPa and electric current for 2 min; process involves almost no change in the grain size. The average grain sizes of WC and Ni for WC-5, 10, and 15 wt%Ni hard materials are about 1.09 ~ 1.29 and 0.31 ~ 0.51 µm, respectively. Vickers hardness and fracture toughness of WC-5, 10, and 15 wt%Ni hard materials are about 1,923 ~ 1,788 kg/mm2 and 13.2 ~ 14.3 MPa.m1/2, respectively. Microstructure and phase analyses of PCASed WC-Ni hard materials are performed.

• Journal of the Korean Society of Food Culture
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• v.37 no.1
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• pp.81-89
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• 2022

This study aimed to evaluate the changes in the content of functional components and antioxidant activity of rice and barley according to the milling process used. A considerable amount of γ-oryzanol was observed in unmilled rice and barley. However, γ-oryzanol was not detected in the rice and barley after the milling process. The highest content of γ-aminobutyric acid (GABA) was observed in the unmilled Keunalbori-1-ho barley. The contents of biotin in all samples also decreased in the milled grains compared to the unmilled grains. The highest content of total polyphenols and flavonoids was observed in the Heuksujeongchal barley, and the highest radical scavenging activity was also found in this grain. The milling process led to a decrease in the content of functional components, including γ-oryzanol, GABA, biotin, polyphenols, and flavonoids in both rice and barley. These results may be useful in the development of processed foods using cereal grains.

• Korean Journal of Breeding Science
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• v.42 no.3
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• pp.302-306
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• 2010

'Migwang' is a new japonica rice variety developed from a cross between SR15926-10-2-3-3-3 having a good canopy architecture and multiple disease resistance, and Iksan431 having a translucent milled rice and good eating-quality with a view of developing a new variety having multiple disease resistance by the rice breeding team at NICS, RDA in 2009. The heading date of this variety is August 15 and later than check variety, Hwaseongbyeo, by four days. 'Migwang' has 75 cm of culm length and 98 spikelets per panicle. This variety showed longer heading delay and higher spikelet sterility than those of Hwaseongbyeo while exposed to cold stress. This variety showed resistance to blast disease and bacterial leaf blight, but susceptible to rice stripe virus and planthoppers. The milled rice of this variety exhibits translucent, clear non-glutinous endosperm and short grain shape. 'Migwang' has better palatability index of cooked rice than that of Hwaseongbyeo. The whole grain rate of milled rice and milled rice recovery of 'Migwang' are higher than those of Hwaseongbyeo as 96.8% and 73.1%, respectively. 'Migwang' has 5.5 MT/ha in milled rice. 'Migwang' could be adaptable to the middle plain area, mid-western and southeastern costal areas and mid-mountainous areas in Korea.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.3
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• pp.201-205
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• 2002

This study was carried out to investigate storability and develop suitable storage method for barley. Rough and milled barley such as Olbori(covered barley), Ssalbori(naked barley) and Chalssalbori (waxy naked barley) were packaged in 3P bag and OPP film bag, respectively, and stored at ambient and low temperature warehouse conditions. The weight loss was higher in milled barley than that of rough barley during barley storage. Acid value, one of the most important factor for grain quality evaluation, was increased from 4.9-9.0 mg KOH/100g to 6.5-19.9mg KOH/100g in milled barley at 16 months after storage. Reducing sugar content was increased while germination and water absorption rates were decreased during barley storage period. In terms of penal taste of boiled barley, rough barley could be stored safely more than one year regardless of storage methods where-ase milled barley stored in ambient temperature ware-house produced nasty flavor at 8 to 10 months after storage.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.6
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• pp.524-530
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• 1993

The experiment was carried out to investigate the changes in physicochemical properties of milled rice harvested in different year and stored for four to sixty four months. The fat acidity of milled rice increased sharply from four to sixteen months storage, and after then it was increased slowly to sixty four months. Amylose, magnesium, potassium content, and K/Mg ratio of milled rice were not changed by storage duration. Water absorption rates of milled rice at 21$^{\circ}C$ and 77$^{\circ}C$, and alkali digestion value were increased by longer storage duration. Difference of water absorption rate between rice samples was greater during initial forty minutes after soaking at 21$^{\circ}C$ and with longer the soaking time at 77$^{\circ}C$. Shorter gel length of rice flour was found with prolonged storage duration, while peak, minimum, cool, breakdown and setback viscosity of gelatinized rice flour on amylograph were increased along with increasing the storage duration. The volume expansion rate during cooking and degree of iodine coloration of cooking water were higher in the longer stored rice compared with shorter one, and the amount of soluble solid in cooking water was significantly decreased in rice stored longer period.

• Korean Journal of Breeding Science
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• v.42 no.3
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• pp.307-312
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• 2010

'Cheonghaejinmi' is a new japonica rice variety developed from three-way cross between Samjiyeon/SR14694-57-4-2-1-3-2-2//Iri402 by the rice breeding team of National Institute of Crop Science, RDA. Heading date of this variety is August 18, 4 days later than that of 'Sobibyeo' in middle plain areas. It has culm length of 78 cm, 125 spikelets per panicle, 92.5% of ripened grain rate, and 23.9 g of 1000-brown rice weight. It showed 12 days of heading delay, and 63% spikelet fertility in cold-water irrigation stress. 'Cheonghaejinmi' is susceptible to blast disease, bacterial blight, virus diseases and plant hoppers. The nitrogen use efficiency of this variety is higher than that of Sobibyeo in low nitrogen application level. Milled rice of 'Cheonghaejinmi' exhibits translucent, clear non-glutinous endosperm and medium short grain. It has 5.9% protein content, 20.3% amylose content, and 0.28 palatability index of cooked rice compared to -0.11 of Hwaseongbyeo. The milled rice yield of 'Cheonghaejinmi' was about 5.31 MT/ha at low nitrogen application level of ordinary season culture. This variety had 98.8% whole grain in milled rice and 76% milling recovery of whole grain. 'Cheonghaejinmi' would be adaptable to middle plain areas and middle-western coastal areas in Korea.

• 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.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.2
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• pp.236-244
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• 1995

This study was carried out to clarify the changes in dry matter weight and physicochemical property of job's tears grain during ripening period. Four varieties of job's tears were seeded at April 20, May 10, and May 30, andgrains were harvested at every 7 days from heading to maturity, The whole seed weight of thick hull varieties, Kimje and Aewon, was higher than that of improved thin hull varieties, Suwon 3 and Suwon 6, from heading to maturity, However, the dehulled grain weight of thin hull variety were higher than that of thick hullvariety from 35 days after heading. The first heading spikelet showed lower 100-grain weight com-pared with the spikelets headed at full blooming stage among the same plant. The increased rate of de hulled grain weight during maturing period was higher in thin hull variety than thick hull one, later seeding date than early seeding, and intermediate headed spikelet than early head-ed one, respectively. As maturing proceeds the protein content of de hulled grain was decreased, alkali digestibility value(ADV) showed a rising trend, and little change was found in gel consistency of milled grain flour. And same trends were found in protein content, ADV and gel consistency as the seeding date was delayed. Among amylogram properties of job's tears flour the maximum, minimum, and final viscosity as well as breakdown were decreased, and set back was increased in later seeding plots

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.5
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• pp.440-444
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• 2006

This study was carried out to compare the grain quality under lodging time and grade at ripening. Ripened grain ratio and 1000-grain weight were higher with lodging of plants at $45^{\circ}$ angle from the ground and increased with crop development. The number of spikelets, as well as the protein and amylose content of the grains, were higher in plants under severe or complete lodging than those under lodging at $45^{\circ}$ angle from the ground. Palatability and sensory evaluation values were higher in plants under lodging at $45^{\circ}C$ angle from the ground than those under complete lodging. Brown rice: rough rice ratio was higher with lodging of plants at $45^{\circ}C$ angle from the ground and increased with crop growth. Milling recovery and milled rice recovery were higher with lodging of plants at $45^{\circ}C$ angle from the ground, whereas chalky grain, cracked grain and damage grains were higher at complete lodging.

• Journal of the Korean Ceramic Society
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• v.35 no.4
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• pp.311-318
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• 1998

The reaction bonded alumina ceramics with reinforced particles which have low shrinkage were pro-duced by blending of SiC or TiC or ZrO2 powders to the mixture of Al metal and Al2O3 powder. The powd-ers were attrition milled isostantically pressed and preheated tio 110$0^{\circ}C$ with a heating rate of $1.5^{\circ}C$/min The specimens were then sintered at the temperature range 1500 to 1$600^{\circ}C$ for 5 hours with a heating rate of 5$^{\circ}C$/min. The specimens showed 5-9% weight gain and 2-9% dimensional expansion through the complete oxidation of Al after preheating up to 11--$^{\circ}C$ the overall dimensional change of the specimens after the reaction sintering at 1500-1$600^{\circ}C$ was 6-12% The maximum densities were 92% theoretical. The fine grain-ed(average grain size :0.4 ${\mu}{\textrm}{m}$) microstructure were observed in the specimen with ZrO2 and SiC. But the microstructure of specimen with TiC was relatively coarse.(average grain size : 2.1 ${\mu}{\textrm}{m}$) The mullite phase was formed by the reaction of Al2O3 and SiO2 in a specimen with SiC. In the TiC contained specimen TiC was oxidized into TiO2 and finally reacted with Al2O3 to form Al2TiO5 during sintering.