• Magazine of the Korea Concrete Institute
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• v.10 no.4
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• pp.153-161
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• 1998

Concrete structures has been deteriorated by and freezing the thawing due to temperature gap. This study was conducted to evaluate durability of concrete which are increasingly demanded recently. Therefore the research of durability must be executed for application of waste foundry sand concrete real structures. Concrete durability properties incorporating waste foundry sand was performed with the variable of W/C ratio. Sand/Waste foundry sand ratio and Air entrainment-Non air entrainment. Cylinder specimens were made and subjected to freezing and thawing cycle at -18$^{\circ}C$ and 4$^{\circ}C$. Dynamic modulus of elasticity were evaluated as F/T cycle increase. The results show that strength of concrete is increased the W/C ratio decrease, the Sand/Waste foundry sand ratio increases when the concrete contains AE agent and decreasing W/C ratio and AE concrete makes improved resistance of freezing and thawing improved. Especially, resistance of freezing and thawing is improved by Fine aggregate/Waste foundry sand ratio which is 50%, 25%, 0% in a row. Therefore it is turn out the waste foundry sand could be applied to concrete from the experiment.

• Journal of Science Education
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• v.43 no.3
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• pp.300-317
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• 2019

This study aims to find how storytelling classes using fairy tales related to science museum exhibits have an effect on positive experience about science. For this study, the theoretical background and preceding studies on the relevance of science education and literature were collected and based on the characteristics of assimilation and the educational value of assimilation, naturally connected to the exhibits in relation to their own life, so that individuals could explore science even out-of-school. Four types of activities were developed by linking four fairy tales mentioned in elementary school textbooks to the G science museum exhibits. Seven elementary school teachers verified the validity of the activity materials. Classes through the developed activity materials were conducted four times in a row, one and a half hours at every turn for 10 students. A positive experience about science test was conducted on the students in a study to confirm that this activity has caused significant changes in science academic emotion among sub-domains of positive experience about science. In order to find the factors that affected the science academic emotion, we interviewed the students in the study and their parents. The results of this study show that the use of fairy tales related to science museum exhibits has led to a significant change in science academic emotion by reducing the burden of learning through the exhibition experience at the science museum, which creates scientific curiosity and recognizes them as a playground.

• The Journal of Engineering Geology
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• v.16 no.2 s.48
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• pp.189-199
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• 2006

This paper presents a field study of the stability of slope collapsed during road construction and proposes a reasonable countermeasure if the current slope is unstable. As a result of slope investigation, it was found that the slope includes five tension cracks and the sliding surface is started from the tension crack and propagated the surface soil layer through weathered rock layer. The slope stability analyses are conducted in case of dry and rainfall seasons. The results indicate that the slope is unstable status. A reinforcement method of slope failure should be selected according to the scale of failure. That is, the scale of slope failure, which is classified small, middle and large size determines the reinforcement method of slope. Since the slope interested in this study is large size failure slope, the reinforcement method to control slope failure is selected stabilizing piles, and seed spray and drainage of surface waterare also selected to remain the factor of safety. The SLOPILE (Ver. 3.0) program is applied in order to do stability analysis of slope reinforced by piles. As the result of analysis, the slope reinforced by a row of piles shows the stable state. It is clearly confirmed that the stabilizing of piles can improve the stability of slope.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.8 no.2
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• pp.107-115
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• 2015

In this paper, a small-area 32-bit differential paired eFuse OTP memory for power ICs is designed. In case of smaller number of rows than that of columns for the OTP memory cell array, a scheme for the cell array reducing the number of SL driver circuits requiring their larger layout areas by routing the SL (source line) lines supplying programming currents for eFuse links in the row direction instead of the column direction as well as a core circuit is proposed. In addition, to solve a failure of being blown for non-blown eFuse links by the electro-migration phenomenon, a regulated voltage of V2V ($=2V{\pm}0.2V$) is used to a RWL (read word line) driver circuit and a BL (bit line) pull-up driver circuit. The layout size of the designed 32-bit eFuse OTP memory is $228.525{\mu}m{\times}105.435{\mu}m$, which is confirmed to be 20.7% smaller than that of the counterpart using the conventional cell array routing, namely $197.485{\mu}m{\times}153.715{\mu}m$.

• Korean Chemical Engineering Research
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• v.43 no.5
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• pp.641-645
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• 2005

Using aqueous solution of 60% ethanol, the isoflavones contained in the Soybean (Chungsun, Korea), Tawon (Suwon, Korea), Jackbean (Hongsung, Korea), Soybean (Jilin, China), Black Soybean (Jilin, China), Kidneybean (Jilin, China) and Soybean (California, U.S.A.) were extracted. In this work, the pretreatment step was composed of agitation extraction, filtration, concentration, ultracentrifuge, and membrane filtration. The analysis by $C_{18}$ column was performed, and the mobile phase applied was linearly changed with A/B of 85/15-65/35 vol% for 50 min (A water/acetic acid, 99.9/0.1 vol%, B acetonitrile/acetic acid, 99.9/0.1 vol%). Among the soybeans tested, the total amounts of the four isoflavones (daidzin, genistin, daidzein, and genistein) extracted by the soybeans from Korea, China and U.S.A. were 1.37, 1.60, and 2.25 mg/g, respectively. It was also found that the total amount of aglycone of daidzein and genistein from soybean (American California) was $144{\mu}g/g$, which was the largest for the soybeans experimented.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.25-34
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• 2008

In this paper, three-dimensional multiblade row unsteady Navier-Stokes simulations at a hot streak temperature ratio of 2.0 have been performed to reveal the effects of rotor tip clearance on the inlet hot streak migration characteristics in low pressure stage of a Vaneless Counter-Rotating Turbine. The hot streak is circular in shape with a diameter equal to 25% of the high pressure turbine stator span. The hot streak center is located at 50% of the span and the leading edge of the high pressure turbine stator. The tip clearance size studied in this paper is 2.0mm(2.59% high pressure turbine rotor height, and 2.09% low pressure turbine rotor height). The numerical results show that the hot streak is not mixed out by the time it reaches the exit of high pressure turbine rotor. The separation of colder and hotter fluid is observed at the inlet of low pressure turbine rotor. Most of hotter fluid migrates towards the rotor pressure surface, and only little hotter fluid migrates to the rotor suction surface when it convects into the low pressure turbine rotor. And the hotter fluid migrated to the tip region of the high pressure turbine rotor impinges on the leading edge of the low pressure turbine rotor after it goes through the high pressure turbine rotor. The migration of the hotter fluid directly results in very high heat load at the leading edge of the low pressure turbine rotor. The migration characteristics of the hot streak in the low pressure turbine rotor are dominated by the combined effects of secondary flow and leakage flow at the tip clearance. The leakage flow trends to drive the hotter fluid towards the blade tip on the pressure surface and to the hub on the suction surface, even partial hotter fluid near the pressure surface is also driven to the rotor suction surface through the tip clearance. Compared with the case without rotor tip clearance, the heat load of the low pressure turbine rotor is intensified due to the effects of the leakage flow. And the numerical results also indicate that the leakage flow effect trends to increase the low pressure turbine rotor outlet temperature at the tip region.

• The Journal of the Korea Contents Association
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• v.21 no.9
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• pp.125-135
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• 2021

Due to the lack of national consensus on the importance and value of the character industry and the lack of recognition of value as a national strategic industry, the development of the character industry is experiencing great difficulties. The purpose of this study is to analyze the economic effects of character industry in China to help establish policies and strategies for the character industry in the future. To this end, this study utilized the China 2017 Industrial Association Table. The analysis results are as follows. China's character industry has a lower production inducement effect than other industries with a column total of 3.45514, and a row total of 1.30015. This shows that China's character industry is still being produced by small and medium-sized companies with a low equity ratio. Second, in the character industry, the index of the sensitivity of dispersion representing the forward linkage effect is 0.01426 and the impact factor is 0.03790, which are all less than 1. Therefore, it can be said to be the final demand manufacturing type.Third, in China character industry's income induction is 0.47690 and the production tax induction effect is -0.04912. It can be seen that the character industry has less income induction and tax burden generated every time the final demand increases by one unit in the entire industry than in other industries.Despite the quantitative growth of the character industry in China, the impact on other industries is low and it is not playing a role as an income-generating industry. Structural improvement is needed for the qualitative development of China's character industry.

• Korean Journal of Heritage: History & Science
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• v.52 no.3
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• pp.240-251
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• 2019

This study examined the manufacturing technology used for the flat iron axes excavated from Ulsan Hadae. Their microstructures were analyzed using metallurgical methods. In addition, a variety of manufacturing technologies were examined and compared using existing research materials on flat iron axes. As a result of analyzing ten flat iron axes, which were excavated in the order that they were laid out in a row in one of the wooden coffin tombs at Ulsan Hadae, Tomb No. 44, it was possible to classify the flat iron axe manufacturing technology and system into three types: 'pure iron - shape processing', 'pure iron - shape processing - carburizing', and 'pure iron - shape processing - carburizing - decarburizing.' All of the flat iron axes were produced by forging, and most of them were made by beating the pure iron into their shapes. In particular, a number of the flat iron axes were reinforced through a carburizing process after shaping the iron. This appears as steel products forming the basis of the steel industry at the time were commonly used as an intermediary material or currency. On the other hand, it was commonly found in all samples that the hardening was not performed after shaping or carburizing. Since the microstructure of the flat iron axes made of pure iron contained a large number of impure inclusions and the result of analyzing the components of the non-metal inclusions showed characteristics of slag which contains a mixture of glass phase and wustite, it is possible that low-temperature reduction was used in the refining process.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.29 no.1
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• pp.62-66
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• 1984

One row of pollen parent to two rows of seed parent (1:2), 2:4 and solid (1:2) planting patterns (PP) were compared in seed parent densities of 3,500, 5,000 and 6,500 plants per 10 ares to determine effects of PP and plant density on growths of seed and pollen plants, and seed yield of seed parent of modified single cross corn hybrid. Planting pattern did not significantly affect agronomic characteristics of seed plant except ear number per 100 plants and seed yield which were greater in solid and 1:2 PP than in 2:4 PP. Significant PP x plant density interaction did not exist for agronomic characteristics of seed parent. In the seed parent, plant height and 100 kernel weight were not affected by plant density, but ear height, ear number per 100 plants, and kernel number per ear were linearly decreased with increased plant densities. Seed yield ranged from 330 to 460 kg per 10 ares and overall yield response to plant density was quadratic. Tassel length and spikelet number per tassel of the pollen parent were significantly affected by PP and plant density. Significant PP x plant density interaction existed for tassel length and spikelet number per tassel. Tassel length and spikelet number per tassel were greater in 1:2 and 2:4 PP compared to solid PP and were greatly reduced with increased plant densities in solid and 1:2 PP. The results indicated that 1:2 or 2:4 PP at around 5,000 plants per 10 ares for seed parent would be suitable for seed production of modified single cross com hybrid.

• Analytical Science and Technology
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• v.19 no.3
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• pp.194-202
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• 2006

In this work, extraction and purification of the possible whitening agents from the Chinese plants; Chrysanthemum morifolium Ramat (xizang cai ju hua), Rhodiola sachalinensis, and Terminalia chebula Retzius have been described. The chopped leaves of Chrysanthemum morifolium Ramat and Terminalia chebula Retzius were added to water and ethyl ether, respectively. Components were separated on a GS310 column ($21.5{\times}500mm$ i.d., $10-15{\mu}m$) and concentrated into four or three portions. The chopped leaves of Rhodiola salientness were added to methanol and separated and concentrated on a column ($C_{18}$ column, $3.9^{\circ}$�F8;300 mm i.d., $15{\mu}m$) into two parts. The whitening effects of extracts were examined by in-vitro melanin production assay, in melana and B16 cells at a concentration of $10{\mu}g/ml$. The ethyl acetate layer of Chrysanthemum morifolium Ramat showed 92% melanin inhibitory at $200{\mu}g/ml$, the extract of Rhodiola sachalinensis showed a whitening effect of about 60% melanin inhibitory, which was more efficient than the whitening effect of arbutin (45.6%). The methanol extract of Terminalia chebula Retzius inhibited melanin expression by 90% at $100{\mu}g/ml$; however, it was toxic to B16 melanoma cells.