• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.4
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• pp.397-404
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• 1994

This experiment was conducted to determine best harvesting time and observe paeoniflorin and some chemical component concentrations of 4-year-old paeonia radix in Euisung and Milyang varieties. Concentrations of paeoniflorin and some chemical components were investigated at 8 periods from Feb. to Oct. Yield of paeonia radix was investigated in Aug. 19, Sep. 18 and Oct. 17. Paeoniflorin and some chemical components were changed seriously at May as flowering time and stabilized after June. The lowest dry matter ratio was 23% and the maximum shrinkage ratio was 47% in May during all the growing stages. Especially, the difference of paeoniflorin concentrations between Euisung and Milyang was about 2%, and paeoniflorin concentrations in Milyang were higher than in Euisung variety during all the stages. Serious infection of disease in October, stem length, stem number per stock and healthful stem ratio in October were more reduced than in August. Yield of paeonia radix was not different from August to September, but that of October harvest was obviously reduced by root-decay-disease. Reasonable harvesting time in 4-year-old paeonia radix was late August to mid-September. When infected shoot rate by disease were severely high, early harvest was more stable in the yield and quality aspects.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.363-363
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• 2014

Ruthenium (Ru) has attractive material properties due to its promising characteristics such as a low resistivity ($7.1{\mu}{\Omega}{\cdot}cm$ in the bulk), a high work function of 4.7 eV, and feasibility for the dry etch process. These properties make Ru films appropriate for various applications in the state-of-art semiconductor device technologies. Thus, it has been widely investigated as an electrode for capacitor in the dynamic random access memory (DRAM), a metal gate for metal-oxide semiconductor field effect transistor (MOSFET), and a seed layer for Cu metallization. Due to the continuous shrinkage of microelectronic devices, better deposition processes for Ru thin films are critically required with excellent step coverages in high aspect ratio (AR) structures. In these respects, atomic layer deposition (ALD) is a viable solution for preparing Ru thin films because it enables atomic-scale control of the film thickness with excellent conformality. A recent investigation reported that the nucleation of ALD-Ru film was enhanced considerably by using a zero-valent metallorganic precursor, compared to the utilization of precursors with higher metal valences. In this study, we will present our research results on the synthesis and characterization of novel ruthenium complexes. The ruthenium compounds were easy synthesized by the reaction of ruthenium halide with appropriate organic ligands in protic solvent, and characterized by NMR, elemental analysis and thermogravimetric analysis. The molecular structures of the complexes were studied by single crystal diffraction. ALD of Ru film was demonstrated using the new Ru metallorganic precursor and O2 as the Ru source and reactant, respectively, at the deposition temperatures of $300-350^{\circ}C$. Self-limited reaction behavior was observed as increasing Ru precursor and O2 pulse time, suggesting that newly developed Ru precursor is applicable for ALD process. Detailed discussions on the chemical and structural properties of Ru thin films as well as its growth behavior using new Ru precursor will be also presented.

• Journal of the Korea Institute of Building Construction
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• v.10 no.5
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• pp.95-102
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• 2010

In recent years, the demand for the development of high quality and cost effective materials, as well as the competition to ensure a diverse and sufficient amount of ready-mixed concrete, has been increasing rapidly. In this experiment, concretes made with different admixtures are blended with each other in different combinations and ratios, in order to identify potential problems. The first test was a slump level test, in which all of the concretes met the required numbers, as they also did in the test for air content. Plain organic acid concrete scored the highest in bleeding amount, but organic acid mix in general showed a similar outcome. In the early measurement of compressive strength, plain naphthalene concrete was the strongest. Of the blends, the 5:5 mix of organic acid and naphthalene was the strongest. In the standard measurement, the 5:5 mix of naphthalene and lignin was the strongest. Tensile strength tests revealed similar results. Length change rate proved to be greater in blended concrete than in plain concrete, and dry shrinkage rate was highest in the 7:3 ratio blends. Through SEM photo analysis, it was confirmed that the 7:3 ratio blends contained more micro-voids. In conclusion, with the exception of a specific few combinations, it was found that the blending of different types of concrete is undesirable due to the delayed coagulation time as well as the early decrease in strength.

• Journal of the Korean Recycled Construction Resources Institute
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• v.3 no.4
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• pp.307-312
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• 2015

This paper addresses mechanical properties and length change performance of the recycled aggregate concretes(RAC) in which natural coarse was replaced by recycled coarse aggregate(RCA) by compressive strength levels(20, 35, 50 MPa). A total of 9 RAC were produced and classified into three series, each of which included three mixes designed with three compressive strength levels of 20 MPa, 35 MPa and 50 MPa and three RCA replacement ratios of 0, 50 and 100%. Physical/Mechanical properties of RAC were tested for slump test, compressive strength, and length change. The test results indicated that the workability of RC could be improved or same by RCA replacement ratios, when compared with that containing no RCA. This is probably because of the RCA shape improving the workability of RAC. Also, the test results showed that the compressive strength was decreased by 9~10% as the RCA replacement ratios increase. However, the length change ratio by the RCA replacement ratios increased regardless of compressive strength levels. At 20 MPa level, the length change ratio was 8~40% which was much higher than that of 4~17% at both 35 and 50 MPa levels. Therefore, it was considered that such admixture addition preventing dry shrinkage is required in order to improve the properties of the RAC at 20 MPa level.

• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.4
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• pp.287-294
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• 2019

GGBFS(Ground Granulated Blast Furnace Slag) has been widely used in concrete for its excellent resistance chloride and chemical attack, however cracks due to hydration heat and dry shrinkage are reported. In many International Standards, GGBFS with low fineness of 3,000 grade is classified for wide commercialization and crack control. In this paper, the mechanical and durability performance of concrete were investigated through two mix proportions; One (BS) has 50% of w/b(water to binder) ratio and 60% replacement ratio with low-fineness GGBFS, and the other (TS) has 50% of w/b and 60% replacement ratio with 4000 grade and FA (Fly Ash). The strength difference between TS and BS concrete was not great from 3 day to 91 day of age, and BS showed excellent performance for chloride diffusion and carbonation resistance. Two mixtures also indicate a high durability index (more than 90.0) for freezing-thawing since they contain sufficient air content. Through improvement of strength in low fineness GGBFS concrete at early age, mass concrete with low hydration heat and high durability can be manufactured.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.11
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• pp.1571-1576
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• 2012

The purpose of this study was to investigate the physicochemical and pasting properties of long-term stored domestic and imported rice supplied for food processing from government-controlled public rice stocks. Goamibyeo, which was bred for processing and harvested in 2011, was selected as the control rice for comparison. Rice was dry-milled, and the amylose contents of stored rice were 12~13%. Stored rice kernels were significantly harder than those of control, whereas damaged starch content and water absorption of flour were not significantly different from those of control. Overall, long-term stored domestic and imported rice showed high peak viscosities along with high viscosities of both hot and cold pastes. Both imported and domestic rice demonstrated insufficient properties for making 100% flat rice noodles or bread. They showed the greatest shrinkage during cooling after baking. Although their levels of cooking loss were less than that of control, stored rice showed a less elastic and softer cooked noodle texture compared to control flour.

• Journal of the Korean GEO-environmental Society
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• v.23 no.9
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• pp.17-23
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• 2022

Using cement as a road subbase is economical, easily modified and supplemented and has excellent road pavement quality control. In addition, cement adheres well to sandy soils without adhesion, and it plays a role of permanently preserving adhesion in viscous soils with adhesion, so it can be widely applied as stable treatment with the advantages of increased strength, reduced compressibility. and improved durability. However, while cement is excellent in terms of strength for a road subbase, the material properties mean that it is difficult to maintain and reinforce when cracks or fractures occur due to dry shrinkage, and the pH increases in the ground due to hexavalent chromium eluting from cement. which can cause environmental problems such as groundwater contamination. Therefore, this study evaluates the usability of alternatives in the road base layer such as environmentally cementitious stabilizer and on-site soil generated from the site. We intend to reduce the environmental damage and evaluate the durability. To evaluate the applicability of the site, Environmental stability test and freeze-thaw test and wetting-drying test was conducted to evaluate the strength characteristics of alternative materials on the road through the limited performance evaluation of environmentally cementitious stabilizer. The test ranges were set at mixing ratios of 10%, 20%, and 30% and ages of three days, and 28 days old to evaluate the early strength and reference strength according to the mixing ratio of the environmentally cementitious stabilizer.

• Journal of the Korea Institute of Construction Safety
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• v.6 no.1
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• pp.12-18
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• 2024

High-rise, large-scale, and diversification of buildings are possible, and the reduction of concrete cross-sections reduces the weight of the structure, thereby increasing or decreasing the height of the floor, securing a large number of floors at the same height, securing a large effective space, and reducing the amount of materials, rebar, and concrete used for designating the foundation floor. In terms of site construction and quality, a low water binder ratio can reduce the occurrence of dry shrinkage and minimize bleeding on the concrete surface. It has the advantage of securing self-fulfilling properties by improving fluidity by using high-performance sensitizers, making it easier to construct the site, and shortening the mold removal period by expressing early strength of concrete. In particular, with the rapid development of concrete-related construction technology in recent years, the application of ultra-high-strength concrete with a design standard strength of 100 MPa or higher is expanding in high-rise buildings. However, although high-rise buildings with more than 120 stories have recently been ordered or scheduled in Korea, the research results of developing ultra-high-strength concrete with more than 130 MPa class considering field applicability and testing and evaluating the actual applicability in the field are insufficient. In this study, in order to confirm the applicability of ultra-high-strength concrete in the field, a preliminary experiment for the member of a reduced simulation was conducted to find the optimal mixing ratio studied through various indoor basic experiments. After that, 130 MPa-class ultra-high-strength concrete was produced in a ready-mixed concrete factory in a mock member similar to the life size, and the flow characteristics, strength characteristics, and hydration heat of concrete were experimentally studied through on-site pump pressing.

• Journal of the Korean Wood Science and Technology
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• v.17 no.1
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• pp.3-11
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• 1989

This study was carried out to investigate the physical and mechanical properties. durability of adhesive bond and paint film for the basic data which were required to determine the suitability as a raw material for furniture the laminated veneer lumber (LVL) with pitch pine (Pinus rigida Mill). The results obtained were as follows; 1) The proper pressing time for making the LVL was over 45 second per milimeter of LVL thickness. 2) The bending strength of the LVL was lower than that of the solid wood but the compressive strength of the LVL was similar to that of the solid wood. The strength increased with the decrease of veneer thickness. 3) The impact bending absorbed energy of the LVL was 0 to 0.3 kg.m/$cm^2$ in the direction of parallel to the grain. The energy of the LVL was lower than that of the solid wood (0.68 kg.m/$cm^2$). 4) In warm water soaking and cold-dry tests, delamination of adhered layers surface crack, swelling, and color change were not found when the hot pressing time was over 45 second per milimeter of LVL thickness. As a result of soak under vacuum test shrinkage in the direction of parallel to the grain was about -1.0 percent and. was about 3.0 percent in the direction of the perpendicular to the grain. 6) The film cacks on the LVL's surface after the wet and cold-dry test were not found at all. 7) In the use of the LVL for interior decoration it was considered that the surface of the LVL be overlaid crossly with fancy veneers of birch and paulownia, etc. This cross overlayirg methods have resulted in few cracks on the fancy veneer.

• Journal of Sericultural and Entomological Science
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• v.23 no.1
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• pp.47-55
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• 1981

Silk textile finishing has been studied for many years by many workers in order to meet more utilities for various endusers. Such studies, however, could not be successful because any natural fibers are hardly change their natures by artificial treating methods. Textile finishing is of course to improve the mechandise qualities and the poor natures of silk so that it may be available as the best textile fiber in the world. Sometimes, famous trade marked textile plays more power than its quality in the silk market, nevertheless, this should be over line of research activities. Meantime, the silk demand has been also transferred from ladies stocking to other clothes since nylon or other synthetic fibers were developed. That is why, the extension of silk demand should be developed by various research works. Specially, silk is known as difficult textile to handle it during washing or ironing process which happened to depress down the silk usage for house wives. In order to solve such problems, the reporter has been worked for many years and now, he believes that he has developed a proper finishing method to coversuch problems. The developed finishing method may be said to eligible with economical aspect and shorten the dry duration after water washing in half against normal silk textile without harming the specific silk nature. As all of us know, silk fiber starts to denature since it was spinned by silkworm and the fiber is formed as overlapped "S" type curves during its concooning process. After it is made as raw silk or sericin silk, it shows as straight line form, but it changes in to waved form in case refining or degumming process in order return to its original spinned form. Such nature is continued during its textile form and ends with hard ironing nature than other textile fibers. Mean while, the silk fiber keeps to continue its denaturing and this is iniciated by repeat of washing and drying which takes many years to reach its final stage, The reporter has found the iniciating denature of silk by his finishing process, with out heat, decreasing the swollen nature which ended with shortening the drying duration after wash. Each washing was carried out by soaking the previously weighed sample in cold water for one hour, then pressed the sample for ten minutes to eliminate its free water component before weighing with same condition. According to this, the treated silk showed much denaturing after the finishing, but the standard silk progressed the denaturing by and by with the repeat of washing and drying, finally reached the same swollen degree of treated silk, Such treating result explains that the treated silk happened to be stebilized nature by the treating immediately. On the other that the treated silk happened to be stebilized nature by the treating immediately. On the other hand, standard silk may reach to such condition by the time of worn out clothes after repeat of washing and drying for many years while the clothes will be no more useful. The decreased swelling nature has brought about the drying period in half against standard silk after all. Not only the tests of tenacity and elongation but also crease resistance recovery, stiffness and shrinkage tests were carried out after each washing and drying which he has found better result on the treated silk textile against the standard silk. The most important thing was to keep the textile feeling of silk by such finishing work before improve any poor nature of silk. The general silk has a nature to absorb smoke or dirt from its surrounding air and reaches to dirty color shade upon such exposure, but the treated one has improved such nature because of its artificial denaturing, another word, it keeps clean longer than the normal silk. Many previous finishing works could improve some specific nature of silk, but it happened to deprave other important natures. The reporters work is, however, specialized to improve the silk to be useful as Wash and Wear Silk without harming its standard natures. So far, this work happened to be a overall innovative finishing method of silk textile.