• Journal of The Korean Society of Grassland and Forage Science
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• v.42 no.3
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• pp.146-154
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• 2022

This experiment was conducted to evaluate the growth characteristics and productivity of silage corn varieties developed in Korea. Corn cultivation was carried out using the experimental field in the Pyeongchang campus of Seoul National University (550 m above sea level). There have 10 domestic cultivars (Gwangpyeongok, Dacheongok, Yanganok, Jangdaok, Cheongdaok, Daanok, Sinhwangok, Sinhwangok II, Pyeonggangok, and Hwangdaok) with one imported cultivar (P1543) which tested as a control, and randomized block design with three replications. Among the 100-grains weight of the seeds, Dacheongok was the heaviest, and the germination rate for each variety was 74.6% on average, while that of Daanok and Sinhwangok were over 90%. Sinhwangok was the fastest in tasseling and silking date. The number of days required to be silking date was as slow as 85 days in Dacheongok, Cheongdaok and Pyeonggangok, and as fast as 80 days or less in Sinhwangok, Sinhwangok II and Hwangdaok. The plant height of P1543 was the highest as 344cm, and Hwangdaok and Daanok were short. In terms of the ratio of ears, Daanok had the highest rate of 60.18%, and Jangdaok and Dacheongok had the lowest. There was no significant difference in dry matter content in stover, but P1543 was generally higher in ear and total dry matter content. The dry matter yield was highest in P1543, and the yield of TDN was significantly higher in P1543 and Yanganok. There was a significant difference in the crude protein content of ears and the dry digestibility of stems (p<0.05), while there was no significant difference in the content of each part or element. Combining the above results, Yanganok was the highest in terms of yield, and Dacheongok, Sinhwangok and Pyeonggangok were also recommended for domestically grown corn varieties in the mountainous regions of Gangwon-do.

• Journal of The Korean Society of Grassland and Forage Science
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• v.42 no.3
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• pp.162-168
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• 2022

This study was carried out to investigate the effects of planting densities on the growth characteristics, dry matter yield, and feed value of "Geukdong 6" (a new variety of corn for feed). The experimental design was arranged in a randomized block design with three replications. Treatments consisted of six planting densities, 60 cm × 25 cm (T1), 60 cm × 30 cm (T2), 70 cm × 25 cm (T3), 70 cm × 30 cm (T4), 80 cm × 25 cm (T5) and 80 cm × 30 cm (T6). All treatments were sown on May 14, 2021, and the harvest was on October 3 (late flowering). Plant length and the number of tillers were the highest in T5 (p<0.05), but the number of leaves and stem diameter were the highest in T6 than in the other treatments (p<0.05). Leaf length, leaf width, and dead leaf were not significantly different among the treatments. Organic matter was highest in T6, and crude protein was highest in T5 (p<0.05). The ether extract was not significantly different among the treatments. Crude fiber, NDF, and ADF were highest in T2 with relatively higher planting density (p<0.05). Calcium and phosphorus were not significantly different among the treatments. TDN content was the highest in T3 (p<0.05). Sugar degree (Brix), fructose, glucose, dextran, isomerose, and inverted sugar were not significantly different among the treatment. Fresh yield, dry matter yield and TDN yield were higher in order of T6 > T5 > T4 > T3 > T2 > T1 (p<0.05). Relatively feed value was higher in order of T3 > T6 > T5 > T1 > T4 > T2 (p<0.05). Based on the above results, planting density could be recommended from 80 cm × 30 cm for efficient production of "Geukdong 6".

• KOREAN JOURNAL OF CROP SCIENCE
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• v.26 no.4
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• pp.350-356
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• 1981

An experiment was carried out to investigate the effect of the vinyl pot size and number of plants per pot on the seedling growth. Dry weight per plant, coefficient of variance and dry weight/fresh weight ratio increased as pot size increased, but competitive index, unit productivity and top/root ratio decreased. Dry , weight per plant decreased with increase in number of plants per pot, but coefficient of variability, competitive index and unit productivity increased. Dry weight per plant of the check plot (1 seedling/3.5cm $\times$ 3.5cm pot) showed little difference between 3 plants/4cm x 4cm pot and 5 plants/5cm x 5cm pot. Temporary transplanting of five plants per 5cm $\times$ 5cm pot saved seedbed area and seedbed materials by 60.9% and labor of transplanting by 36.3% as compared with check plot.

• Nuclear Engineering and Technology
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• v.25 no.2
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• pp.248-254
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• 1993

The purpose of this study is to evaluate the thermal safety for dry transport of a shipping cask. Analysis condition was based on an ambient temperature of 38$^{\circ}C$ for normal heat condition. The cask was designed to carry 4PWR spent fuel assemblies with a burnup of 38,000 MWD/MTU and 3 years of cooling time. Thermal analysis was carried out by using the COBRA-SFS code. The fuel cavity was considered to be filled with air, nitrogen or helium gas for dry transport. The results of analysis showed that the maximum temperatures of fuel rod cladding in air and helium cavity would be 277$^{\circ}C$ and 226$^{\circ}C$, respectively, for 3 years of cooling time. These values were less than the specified temperature to maintain the thermal integrity of fuel assembly for dry transport.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.109-109
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• 2022

The global population is increasing every year, and the amount of food waste is also increasing. Direct landfilling of food waste has been prohibited since 2005, and in accordance with the London Convention in 2013, the discharge of livestock manure, sewage sludge, and food waste into the sea is prohibited. In the case of incineration to treat the discharged food waste, the heat point is lowered due to the moisture in the food waste itself, so fuel must be added. Therefore, this study was conducted to get basic data for setting the limit of application by investigating the growth and yield of crops after treating food waste dry powder mixed fertilizer (MF) on red pepper. In the experiment, continuous cultivation was carried out for two years in 2021 (1st year) and 2022 (2nd year). The treatment groups were set as Not Treatment (NT), Chemical Fertilizer (CF), Mixed Fertilizer (MF), Mixed Fertilizer×2 (MF×2). After harvest, crop growth and yield were investigated. As a result of the 1st years of growth survey, CF, MF, MF×2 show significant difference in shoot length compared to NT. About fresh weight and dry weight, CF show significant difference compared to NT. The 2nd years of growth survey, the shoot and root length, fresh weight did not show significant difference with NT. In case of dry weight, MF is significant increased compared to NT. As a result of the yield survey of the 1st year, all treatment groups did not show a significance in yield compared to the NT. In case of 2nd year, all treatment groups show significantly increased value compared to NT. The yield of MF was highest among the treatment groups. In the future, it is thought that it is necessary to quantitatively evaluate the effect of food waste dry powder mixed fertilizer through additional experiments and continuous cultivation, and to establish an appropriate amount of use and establishment of a manual based on this.

• Journal of the Korean Geotechnical Society
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• v.21 no.10
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• pp.123-131
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• 2005

In the present study, laboratory pull-out tests with screw anchors are carried out to investigate behavior characteristics of the anchors used in foundation system of underground structures which are applied to uplifting seepage forces. Small scaled pull-out tests in sand under saturated condition and dry condition were carried out. For estimating the group effects of the anchors, the upward displacement and the pullout load varied with spacing of the anchor were observed. The test results were compared with theoretical equation for the ultimate pull-out force. Also, the result of tests can be used to the finite element analysis program, $PENTAGON^{2D}$.

• Restorative Dentistry and Endodontics
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• v.38 no.4
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• pp.234-240
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• 2013

Objectives: This study evaluated the effects of intraradicular moisture on the pushout bond strength of a fibre post luted with several self-adhesive resin cements. Materials and Methods: Endodontically treated root canals were treated with one of three luting cements: (1) RelyX U100, (2) Clearfil SA, and (3) G-Cem. Roots were then divided into four subgroups according to the moisture condition tested: (I) dry: excess water removed with paper points followed by dehydration with 95% ethanol, (II) normal moisture: canals blot-dried with paper points until appearing dry, (III) moist: canals dried by low vacuum using a Luer adapter, and (IV) wet: canals remained totally flooded. Two 1-mm-thick slices were obtained from each root sample and bond strength was measured using a push-out test setup. The data were analysed using a two-way analysis of variance and the Bonferroni post hoc test with p = 0.05. Results: Statistical analysis demonstrated that moisture levels had a significant effect on the bond strength of luting cements (p < 0.05), with the exception of G-Cem. RelyX U100 displayed the highest bond strength under moist conditions (III). Clearfil SA had the highest bond strength under normal moisture conditions (II). Statistical ranking of bond strength values was as follows: RelyX U100 > Clearfil SA > G-Cem. Conclusions: The degree of residual moisture significantly affected the adhesion of luting cements to radicular dentine.

• Solar Energy
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• v.11 no.1
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• pp.69-77
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• 1991

A two-phase closed thermosyphon with circular fins was used as the heat transfer device for storing the thermal energy in paraffin wax. Experiments were carried out for 4, 6 and 8 fins and for various initial temperatures of the wax and power inputs. Heat transfer characteristics along the heat flow path were investigated as well as the overall performance of the system. Some of the important results are as follows:(1) The thermosyphon heat transfer coefficient and the overall heat transfer coefficient increased with the number of fins, whereas the heat transfer coefficient between the fin and the wax decreased; (2) Facilitation of heat transfer by the fins seemed to alleviate the dry-out phenomenon that had been reported to occur in case of bare thermosyphon; and (3) The horizontal fins had adverse effect of subduing a full scale convection in the wax, and the increase of the number of fins delayed the onset of local convection between the fins.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.474-477
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• 2005

The Industrial development and the Increase in population have brought out a rapid increase of wastewater discharge. To deal with this matter, much estimate has been spend on construction and management of a large scale sewage treatment plant. Although every effort has been carried out, river water quality has no significantly improved. Especially. the aggravation of the water quality in dry season is brought out a serious social problem. The purpose of this study Is the development of an optimal water quality management technique considering the efficient control of the multiple pollutant load associated with the total pollutant load control. A GUI(Graphical User Interface) system named 'QL2-XP' model is developed by object-oriencted language for the user convenience and practical usage. Suggested GUI system consist of hydraulic analysis. water quality analysis, optimized model calibration processes, and postprocessing the simulation results.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.343-346
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• 2003

Confirmation of a damage degree and repair about a damage part are very hard for an underwater structure. And quality control of a construction is very complicated even if repair work is carried out on a damaged structure because repair work is carried out in water. If repair work is carried out while a defect part of the structure which there is in water keeps dry state, a efficient of repair is maximized. However, as for the repair technology about an underwater structure, a systematic researcher is not enough because of the environmental trouble. And, as for the effect about repair method to be applied to a currently underwater structure, it is not certainly proved. In this study The repair work of an underwater structure damaged applied the method that used a fiber panel form work. And a efficient of structure repaired was evaluated.