• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.37 no.2
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• pp.164-168
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• 2024

(La_0.7Sr_0.3)(Mn_1-xFe_x)O₃ (LSMFO) (x = 0.03, 0.06, 0.09, 0.12) precursor solution are prepared by sol-gel method. LSMFO thin films are fabricated by the spin-coating method on Pt/Ti/SiO₂/Si substrate, and the sintering temperature and time are 800℃ and 1 hr, respectively. The average thickness of the 6-times coated LSMFO films is about 181 to 190 nm and average grain size is about 18 to 20 nm. As the amount of Fe added in the LSMFO thin film increased, the resistivity decreased, and the TCR and B_25/65-value increased. Electrical resistivity, TCR and B_25/65-value of the (La_0.7Sr_0.3)(Mn_0.88Fe_0.12)O₃ thin film are 0.0136 mΩ-cm, 0.358%/℃, and 328 K at room temperature, respectively. The resistivity properties of LSMFO thin films matched well with Mott's VRH model.

• Korean Journal of Plant Resources
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• v.20 no.1
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• pp.43-49
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• 2007

This study was conducted to examine the pattern and characteristics of flowering and leaf emergence for twenty two kinds of the genus of Lycoris sp. One species of Lycoris was flowered on July to August, twelve species on August, and nine species on September. Shape of flowers were as follows : Nine species belong to L. radiara-shaped flower, seven species L. squamigera-shaped flower, and seven species the intermediate type. Flower color of three kind were an order of descent red and pink. seven kind white, four kind yellow, three kind orange, and two kind purple colors. Ten Lycoris species were good fertile, and two kinds were poor fertile. The average length of pollen grain was ranged from $48.53\;to\;88.62{\mu}m$, and the width from $22.87\;to\;33.67{\mu}m$. Eleven kinds were spring-leaf emergence type, and ten kind autumn-leaf emergence types. Hunter values in leaves were as follows : $L^*$ value was ranged from 31.6 to 45.2; $a^*$ values from -6.74 to -17.46; $b^*$ values from 6.19 to 21.89 Leaf width was ranged from 0.90 to 2.35cm, and its shape was oblong. The length of epidermal cells was 0.33 to 0.75mm, and the width was $38.53\;to\;90.00{\mu}m$. Most of stomata were distributed in the back side of leaves. The length of stomata was ranged from $67.12\;to\;104.89{\mu}m$, and its width was from $14.90\;to\;71.52{\mu}m$.

• Economic and Environmental Geology
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• v.45 no.5
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• pp.487-502
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• 2012

This paper is focused on mineral compositions, microstructures and distributional characters of remained grains in the fault rocks collected from a fault developed in Yongdang-ri, Yangbuk-myeon, Gyeongju City, Korea, using X-ray diffraction (XRD), optical microscope, laser grain size analysis and fractal dimension analysis methods. The exposed fault core zone is about 1.5 meter thick. On the average, the breccia zone is 1.2 meter and the gouge zone is 20cm thick, respectively. XRD results show that the breccia zone consists predominantly of rock-forming minerals including quartz and feldspar, but the gouge zone consists of abundant clay minerals such as chlorite, illite and kaolinite. Mineral vein, pyrite and altered minerals commonly observed in the fault rock support evidence of fault activity associated with hydrothermal alteration. Fractal dimensions based on box counting, image analysis and laser particle analysis suggest that mineral grains in the fault rock underwent fracturing process as well as abrasion that gave rise to diminution of grains during the fault activity. Fractal dimensions(D-values) calculated by three methods gradually increase from the breccia zone to the gouge zone which has commonly high D-values. There are no noticeable changes in D-values in the gouge zone with trend being constant. It means that the bulk-crushing process of mineral grains in the breccia zone was predominant, whereas abrasion of mineral grains in the gouge zone took place by continuous fault activity. It means that the bulk-crushing process of mineral grains in the breccia zone was predominant, whereas abrasion of mineral grains in the gouge zone took place by continuous fault activity. Mineral compositions in the fault zone and peculiar trends in grain distribution indicate that multiple fault activity had a considerable influence on the evolution of fault zones, together with hydrothermal alteration. Meanwhile, fractal dimension values(D) in the fault rock should be used with caution because there is possibility that different values are unexpectedly obtained depending on the measurement methods available even in the same sample.

• Journal of Biosystems Engineering
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• v.5 no.1
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• pp.1-14
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• 1980

Threshing operation may be one of the most important processes in the paddy post-production system as far as the grain loss and labor requirement are concerned . head-feeding type threshers commercially available now in Korea originally were developed for threshing dry paddy in the range of 15 to 17 % in wet basis. However, threshing wet-paddy with the grain moisture content above 20 % has been strongly recommended, especially for new high-yielding Indica -type varieties ; (1) to reduce high grain loss incurred due to the handling operations, and (2) to prevent the quantitative and qualitative loss of milled -rice when unthreshed grains are rewetted due to the rainfall. The objective of this study were to investigate the adaptability of both a head-feeding type thresher and a throw-in type thresher to wet-paddy , and to find out the possiblilities of improving the components of these threshers threshing. Four varieties, Suweon 264 and Milyang 24 as Tongil sister line varieties, minehikari and Jinhueng as Japonica-type varieties, were used at the different levels of the moisture content of grains. Both the feed rate and the cylinder speed were varied for each material and each machine. The thresher output quality , composition of tailing return, and separating loss were analyzed from the sampels taken at each treatment. A separate experiment for measurement opf the power requirement of the head-feeding type thresher was also performed. The results are summarized as follows : 1. There was a difference in the thresher output quality between rice varieties. In case of wet-paddy threshing at 550 rpm , grains with branchlet and torn heads for the Suweon 264 were 12 % and 7 % of the total output in weight, respectively, and for the Minehikari 4.5 % and 2 % respectively. In case of dry paddy threshing , those for the Suweon 264 were 8 % and 5% , and for the Minehikari 4% and 1% respectively. However, those for the Milyang 23 , which is highly susceptable to shattering, were much lower with 1 % and 0.5% respectively, regardless of the moisture content of the paddy. Therefore, it is desirable to breed rice varieties of the same physical properties as well as to improve a thresher adaptable to all the varieties. Torn heads, which increased with the moisture content of rall the varieties except the Milyang 23 , decreased as the cylinder speed increased, but grains with branchlet didnt decrease. The damaged kernels increased with the cylinder speed. 3. The thresher output quality was not affected much by the feed rate. But grains with branchlet and torn heads increased slightly with the feed rate for the head-feeding type thresher since higher resistance lowered at the cylinder speed. 4. In order to reduce grains with branchlet and torn heads in wet-paddy threshing , it is desirable to improve the head-feeding type thresher by developing a new type of cylinder which to not give excess impact on kernels or a concave which has differenct sizes of holes at different locations along the cylinder. 5. For the head-feeding type thresher, there was a difference in separating loss between the varieties. At the cylinder speed of 600 rpm the separating losses for the Minehikari and the Suweon 264 were 1.2% and 0.6% respectively. The separating loss of the head-feeding type thresher was not affected by the moisture content of paddy while that of the Mini-aged thresher increased with the moisture content. 6. From the analysis of the tailings return , to appeared that the tailings return mechanism didn't function properly because lots of single grains and rubbishes were unnecessarily returned. 7. Adding a vibrating sieve to the head-feeding type thresher could increase the efficiency of separation. Consequently , the tailing return mechanism would function properly since unnecessary return could be educed greatly. 8. The power required for the head-feeding type thresher was not affected by the moisture content of paddy, but the average power increased linearly with the feed rate. The power also increased with the cylinder speed.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.6
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• pp.548-555
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• 1994

To compare the tolerance of crops to acid rain at different growth stages a simulated acid rain (SAR) of pH 2.7 was applied to rice, soybean, and hot pepper from vegetative growth stage to harvest (Veget.-Harvest) and from reproductive growth stage to harvest (Reprod.-Harvest). Visual damages of crops by SAR were greater in the order of rice < hot pepper < soybean and greater at Veget.-Harvest than at Reprod.-Harvest treatment. Chlorophyll content of all crops was greater in the order of Veget.-Harvest < Reprod.-Harvest treatment < control, but photosynthetic activity was not affected by SAR treatments. Nitrogen concentration and uptake of rice plants at harvest were similar among SAR treatments, but those of soybean and hot pepper were greater at Veget.-Harvest treatment than at Reprod.-Harvest treatment or control. Sulfur concentration of all crops was not affected by SAR treatments, but total sulfur uptake of soybean was greater in SAR treatments than untreated control. Grain yield of rice and soybean was not affected by SAR although grain fertility, percent ripened grains, and 1,000-grain weight of rice at Veget.-Harvest treatment were lower compared with Reprod.-Harvest treatment or control. Fruit dry weight of hot pepper was greater in the order of Veget.-Harvest < Reprod.-Harvest < control due to decreased fruit number per plant and average fruit weight. At one time application of SAR at flowering stage, brown spots were observed on the spikelets of rice at below pH 2.3. Petals of soybean and hot pepper were wilted at pH below 1. 7 and 2.0, respectively, but fruit setting was not affected by the pH of the SRA.

• Korean Journal of Agricultural Science
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• v.3 no.2
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• pp.145-151
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• 1976

This study was conducted to determine the effect of slaked lime and straw used on the soil pH in the flooded condition and yield of rice grown in AKIOCHI paddy field and their residual effects on the rice plants. The results obtained were summarized as follow: when lime and straw were applied, there was on the average 41% of yield increase over plots treated with three elements of chemical fertilizers. When lime plus straw were used, the growth rate at later stage of rice plant was prominent. Damage due to helminthosporium and blast were found less, the rate of lower-leaf death was low, and grain number, per head, filled grain ratio, and weight of rice grain were higher than control. When lime plus straw were used, higher amount of silicate, calcium, nitrogen and potassium was found in the plants at heading stage. The residual effects of lime plus straw were 20% in the first year, about 10% in the second year and 5% in the third year, respectively. Soil pH was affected by both straw and slaked lime, and it was fixed about 8 days after applying in the flooded condition. The following formulae was suggested from the results in the flooded conditions. $$pH=5.5293+8.6007X_1+2.7836X_2-{6.7422X_1}^2-{1.8522X_2}^2-7.000X_1X_2$$ ($X_1$=slaked lime, $X_2$=straw)

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.7
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• pp.624-631
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• 2006

This study was conducted to make clustering analysis based on major physicochemical characteristics related to palatability of cooked rice. 89 Korea-bred japonica rice cultivars could be largely classified into two groups, that is, Dongjinbyeo and Ilpumbyeo groups. The Ilpumbyeo group was divided into two subgroups; Ilpumbyeo and Chucheongbyeo groups. The two major rice groups showed significant difference in viscogram properties of rice flour. Ilpumbyeo group revealed slightly higher estimates of viscogram traits as compared with Dongiinbyeo group in average. Early-maturing rice group showed slighly lower estimates of taste meter and higher protein content compared with medium or medium late maturing ones. Also, early and medium-maturing groups exhibited slightly higher estimates of peak, hot and breakdown viscosities but lower estimates of consistenency and setback viscosities compared with medium-late-maturing one. The rice cultivars developed in 2000's revealed slightly higher estimates of peak, hot, cool and consistency viscosities compared with those in $1980's{\sim}1990's$. The grain quality properties significantly associated with the esimates of Toyo taste meter were protein and amylose contents and hot viscosity. The lower protein content and hot viscosity and the higher amylose content, the higher estimates of the taster meter. The protein content was highly negatively correlated with amylose content of milled rice. The important quality components contributed to multiple regression formula for estimating the Toyo taster meter values were protein content, alkali digestion value, and hot viscosity. The fittness of this formula was about 49% along with the coefficients of determination.

• Magazine of the Korean Society of Agricultural Engineers
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• v.19 no.1
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• pp.4312-4322
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• 1977

In order to investigate the effect of the water content and the accelerated curing on the strength of the soil-cement mixtures, laboratory test of soil cement mixtures was performed at five levels of water content, four levels of accelerated curing temperatures, three levels of normal curing periods, and six levels of accelerated curing time. Also this study was carried out to investigate the effect of grain size distribution of 21 types of soils on the strength of soil-cement mixtures at four levels of cement content and three levels of curing time. The results are summarized as follows: 1. Optimum moisture content increased with increase of the cement content, but maximum dry density was changed ununiformly with cement content. Water content corresponding to the maximum strength was a little higher than the optimum moisture content along the increase of cement content. 2. In molding the specimens with the optimum moisture content, the maximum strength appeared at the wet side of the optimum moisture content. 3. According to increase of curing temperature as 30, 40, 50, and 60$^{\circ}C$, unconiiend compressive strength of soil-cement mixtures increased, the rate of increase at the early curing period was large, and approximately 120 hours was suifficient to harden soil-cement mixtures completely. 4. The strength of soil-cement mixtures at the curing temperature of 10$^{\circ}C$ decreased at the rate of 30 to 50 percent than at the curing temperature of 20$^{\circ}C$, and the strength of soil-cement mixtures at the curing temperature of 0$^{\circ}C$ increased a little with increase of curing time. 5. Although the strength of soil-cement mixtures seemed to be a little affected by the temperature difference between day time and night, it was recommended that reasonable working period was the duration from July to August of which average maximum temperature of Korea was approximately 30$^{\circ}C$. 6. Accelerated curing time corresponding to the normal curing time of 28-day was shorten with increase of curing temperature, also it was a little affected by the cement. Accelerated curing time that the strength of soil-cement mixtures for the cement of 9 percent and the curing temperature of 60was shorten with increase of curing temperature, also it was a little affected by the cement. Accelerated curing time that the strength of soil-cement mix- tures for the cement of 9 percent and the curing temperature of 60$^{\circ}C$ was 45 hours at the KY sample, 50 hours at the MH, 40 hours at the SS, and 34 hours at the JJ respectively. 7. Accelerated curing time was depended upon the grain size distribution of soil, it decreased with increase the percent passing of No. 200 sieve. 8. Relationship between the normal curing times and the accelerated curing times showed that there was a linear relationship between them, its slope decreased with increase of curing temperature. 9. The most reasonable soil of the soil-cement mixtures was the sandy loam which was a well graded soil. Assuming the base of road requiring 7-day strength of 21 kg/$\textrm{cm}^2$ being used, the soil-cement mixtures could be obtained with adding 6 percent of cement in such a sails S-7, S-8, S-9, S-10, S-11, S-12, S-13. 10. The regression equation between the 28-day and the 7-day strength was obtained as follow; q28=1.12q7,+6.5(r=0.96).

• KOREAN JOURNAL OF CROP SCIENCE
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• v.64 no.4
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• pp.395-405
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• 2019

A recent assessment by the Intergovernmental Panel on Climate Change projected that the global average surface temperature will increase by a value 1.5℃ from 2030 to 2052. In this study, we used a temperature gradient chamber that mimicked field conditions to evaluate the effect of increased air temperature on phenology, yield components, protein content, and oil content, to assess soybean growth. In 2017 and 2018, 'Deawonkong', 'Pungsannamulkong', and 'Deapungkong' cultivars were grown in three temperature gradient chambers. Four temperature treatment groups were established by dividing the rows along temperature regimes: ambient temperature + 1℃ (aT+1), ambient temperature + 2℃ (aT+2), ambient temperature + 3℃ (aT+3), ambient temperature + 4℃ (aT+4). Year, cultivar, and temperature treatments significantly affected yield components and seed yield. In 2017, the flowering stage of 'Deawon' and 'Pungsannamul' cultivars in the aT+4 group was delayed compared to the flowering stage of those in the aT+1 group. In 2018, the flowering stage of 'Deawon' and 'Pungsannamul' was delayed at all temperature gradients, owing to high temperature stress, whereas 'Deapung' was regularly flowering in 2017 and 2018. The duration of the grain filling period was six days shorter in 2018 than in 2017 because of high temperature stress. The total number of pods per ㎡ for 'Deawon' and 'Pungsannamul' was 48.8 and 41.5% lower in 2018 than in 2017, respectively, whereas 'Deapung' increased by 6.3%. The 100-seed weight of 'Deawon' and 'Deapung' was 29.2 and 32.1% lower, respectively. However, 'Pungsannamul' decreased by 14.7%. The protein and oil content was lower during the grain filling period in 2018 than in the same period in 2017 because of high temperature stress. In contrast, the oil content in 'Deapung' was higher in 2018 than in 2017. Our results showed that increased temperature during the grain filling period was significantly and negatively correlated with pod number, 100-seed weight, protein content, and oil content.

• Journal of the Korean Magnetics Society
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• v.16 no.5
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• pp.255-260
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• 2006

The basic composition of Ni-Zn ferrite was $(Ni_{0.35}Cu_{0.2}Zn_{0.45})_{1.02}(Fe_2O_3)_{0.98}$ (group A) and $(Ni_{0.4}Cu_{0.2}Zn_{0.4})_{1.02}(Fe_2O_3)_{0.98}$(group B) with additional 0.1 mol% $CaCO_3$ and 0.03 mol% $V_2O_5$. For high permeability and acceleration of grain growth, $CaCO_3$ and $V_2O_5$ was added. The mixture of the law materials was calcinated at $600^{\circ}C$ for 2 hours and then milled. The compacts of toroidal type were sintered at different temperature ($1,050^{\circ}C,\;1,070^{\circ}C,\;1,100^{\circ}C$) for 2 hours in air followed by an air cooling. Then, effects of various composition and sintering temperatures on the microstructure and physical properties such as density, resistivity, magnetic induction, coercive force, initial permeability, quality factor, and curie temperature of the Ni-Zn ferrite were investigated. The density of the Ni-Zn ferrite was $4.90{\sim}5.10g/cm^3$, resistivity revealed $10^8{\sim}10^{12}{\Omega}-cm$. The average grain size increased with the increase of sintering temperatures. The magnetic properties obtained from the aforementioned Ni-Zn ferrite specimens were 4,000 gauss for the maximum induction, 0.25 oersted for the coercive force, 2,997 for the initial permeability, 208 for the quality factor, and $202^{\circ}C$ for the curie temperature. The physical properties indicated that the specimens could be utilized as the core of microwave communication and high permeability deflection yoke of high permeability.