• Journal of Korean Society of Forest Science
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• v.98 no.4
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• pp.504-511
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• 2009

This study to understand the production cost of cultivation in chestnut tree (Castanea spp.) as a result of a survey conducted of 227 farmers is as follows. In full-time farmer, average cultivation area was 5.5 hectares and average chestnut production was 1.6 tons per hectare. In chestnut sale type, more than 73% of total production was sold by Nong-hyup (7an agricultural cooperative association) and intermediaries, and also proportion of nut size grade was 18% in special-large nut, following 49% in large nut, 25% in middle nut and 8% in small nut. There was considerable difference among cultivated regions in gross income, whereas total average gross income was 2,103 thousand KRW per hectare and 66.4% of it was used in management expenses. Finally the chestnut cultivated farmers have a yearly income of 706 thousands KRW (net income rate 33.6%). As peculiarity of regional production cost, a low tree farm in height and a labor intensive growing helped the improved quality of the chestnut so, on average, 2,161 thousand KRW per hectare of the income of the Chungnam was raised. However caused by an old-age of chestnut trees, there was a little input to management expenses and it resulted in low productivity in the Jeonnam and the Gyeongnam.

• Journal of Korean Society of Forest Science
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• v.97 no.3
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• pp.221-228
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• 2008

This study was conducted to understand the effect of the different treatment level of head back pruning (HBP) on flowering, fruiting and nut qualities. The average number of pistillate flowers per bearing mother branch (BMB) ranged greatly from 0.5 to 60.0. For all cultivars as the level of HBP treatment increases, the number of pistillate flowers per bearing branch (BB) and BMB decreased. For all cultivars the number of branches developed per BMB began to decrease above 30% HBP treatment level. The number of burrs per BB ranged from 1.0 to 2.0. Within 'Daebo' the number of burrs per BB increased with increasing HBP treatment level. The rate of fallen fruits was the lowest of 22.6% at the 50% HBP treatment level of 'Tsukuba', whereas the rate was the highest in 'Pyeonggi'. Nut weight increased with decreasing the number of burrs per BB. Nut yield per BMB showed a tendency of decreasing with increasing the HBP treatment level. Within a HBP treatment level nut grade indicating nut quality varied greatly among cultivars. For all cultivars except for 'Pyeonggi', the proportion of specially large nuts above the average weight increased as the HBP treatment level increased. The soluble solids content showed no significant difference among the HBP treatment levels just right after harvesting of nuts. After 8 weeks of harvesting, however, the soluble solids content increased about 3.3% to 5.3%. and was highest at the 50% HBP treatment level. There were no significant differences among the HBP treatment levels and cultivars in the nut hardness which is highly related to the storage as well as the initial soluble solid content.

• Journal of Korean Society of Forest Science
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• v.100 no.3
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• pp.432-440
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• 2011

The objective of this study was to investigate growth and fruiting characteristics (e.g., nut qualities) of chestnut (Castanea cerenata) after applying various fertilizer treatments at the cultivation site in Suncheon. Fertilizer treatments were designed as follow: liquid fertilizer, chemical fertilizer, organic fertilizer, and control. Both liquid and chemical fertilizer treatments provided the best growth in height and basal diameter. In addition, these two treatments were very effective for crown width of the trees between both east-west and north-south orientation. The liquid fertilizer treatment was effective on total length of the fruiting branch and length of the bearing to terminate part. Both liquid and chemical fertilizer treatments produced the longest length of basal to bearing part compared to the other two treatments. The liquid fertilizer treatment showed the most thickened basal diameter of the fruiting branch and the greatest diameter of above and below the bearing burr part. Elongation Index of the fruiting branch (EI) was the highest with liquid fertilizer treatment and the remaining four indices (Production Index of fruiting branch, PI; Ratio of Diameter between below and above bearing burr part, RD; Growth Index of fruiting branch diameter, GI; Thickness Index of fruiting branch or dormant branch, TI) were the highest with the chemical fertilizer treatment. Total number of produced branch per fruiting mother branch and number of small and weak branches per fruiting mother branch were highest on the control and liquid fertilizer treatment; however, all treatments produced similar numbers. The chemical and organic fertilizer treatments produced a high number of fruiting branches per fruiting mother branch, while organic and liquid fertilizer treatments produced a high number of burr per fruiting branch. The rate of commercializing on the basis of nut weight and quantity was higher on control (87.5%) than chemical fertilizer treatment (84.6%); however, the rate was even lower on liquid fertilizer treatment (84.3%) and organic fertilizer treatment (82.7%). The liquid fertilizer treatment showed the highest average of nut weight, while chemical fertilizer treatment showed the highest average number of fruiting burr. There was no significant difference in average number of normal nuts per burr among treatments. The yield per tree was high on chemical (8.2 kg) and liquid (8.0 kg) fertilizer treatments, but there was no significant difference among treatments. In the rate of nut grade on the basis of nut weight and quantity, the liquid fertilizer treatment, 43.5% and 34.3% more than large nut respectively, produced higher value chestnuts compared to other treatments.

• Food Quality and Culture
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• v.2 no.2
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• pp.80-84
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• 2008

In this study, sixth grade school children in the Guri area were surveyed via questionnaire regarding their sociodemographic characteristics, snacking patterns, and intakes of different food groups and sugared snacks. Students with employed mothers had more frequent snacking events and were more dependent on store-purchased snacks compared to those having an unemployed mother. A high consumption of snack sugar was associated with a higher dietary diversity score. There was a positive relationship between snack sugar intake and the intakes of meat and dairy products and foods in the oil and nut group, respectively. A high snack sugar intake had a negative effect on fruit intake. Specific nutrient intake data will be required before conclusions can be made on whether nutrient imbalances are a concern in elementary school children having sweet snacks. Yet, the current data indicate that an increased snack sugar intake can decrease fruit intake, which could result in certain nutrient deficits. Specific dietary guidance may be necessary to address the snacking habits of elementary school children.

• Steel and Composite Structures
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• v.50 no.3
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• pp.319-336
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• 2024

Ultra-high-performance concrete (UHPC) has attracted increasing attention in prefabricated steel-concrete composite beams as achieving the onsite construction time savings and structural performance improvement. The inferior replacement and removal efficiency of conventional prefabricated steel-UHPC composite beams (PSUCBs) has thwarted its sustainable applications because of the widely used welded-connectors. Single embedded nut bolted shear connectors (SENBs) have recently introduced as an attempt to enhance demountability of PSUCBs. An in-depth exploration of the mechanical behavior of SENBs in UHPC is necessary to evidence feasibilities of corresponding PSUCBs. However, existing research has been limited to SENB arrangement impacts and lacked considerations on SENB geometric configuration counterparts. To this end, this paper performed twenty push-out tests and theoretical analyses on the shear performance and design recommendation of SENBs. Key test parameters comprised the diameter and grade of SENBs, degree and sequence of pretension, concrete casting method and connector type. Test results indicated that both diameters and grades of bolts exerted remarkable impacts on the SENB shear performance with respect to the shear and frictional responses. Also, there was limited influence of the bolt preload degrees on the shear capacity and ductility of SENBs, but non-negligible contributions to their corresponding frictional resistance and initial shear stiffness. Moreover, inverse pretension sequences or monolithic cast slabs presented slight improvements in the ultimate shear and slip capacity. Finally, design-oriented models with higher accuracy were introduced for predictions of the ultimate shear resistance and load-slip relationship of SENBs in PSUCBs.

• Journal of Ocean Engineering and Technology
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• v.2 no.2
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• pp.130-137
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• 1988

This thesis introduced that character of a treatment technique for a mading synthetic resin Hifiow-Ring. The material system of packings make an experiment air$NH_{3}$/air$H_{2}SO_{4}$, $SO_{2}$-air/NaOH, $NH_{3}$-air/$/H_{2}SO_{4}$ under general conditions. Lattices packing compared with conventional packings was proved low pressure loss and high separation efficiency for high loading per trans unit. And an inflow materal tested for absorption and rectification, it made an experiment under a range regular temperature, low energy and small amount of money. That made possible in simple equation, volume material tranfer coefficient$\beta_{L}$ . a by absorption or $\beta_{V}$ .a calculated in all range loading. The peculiarity pressure loss $\Delta\;P/NUT_{ov}$ for Hiflow-ring contributed to a fall cost of energy, a grade number of a vacuum rectification and absorption calculation.