• Applied Biological Chemistry
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• v.20 no.3
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• pp.279-284
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• 1977

Like that mentioned in the 2nd report, because of panel's sense of psychological and physiological responsibility caused by multi-samples, great errors in experimental results are expected. So as to cut down these errors, the new method called "Pair Comparision with Standard" that reduces test frequency and is superior in detecting power is designed, and its mathematical model is proposed. This paper suggests that this method can be used for screening test that, first of all, selects 4-5 of multi-samples and the most efficient sensory evaluation method in laboratorial quality study is that, after screening by this method, Trio Paired Comparison for the final justification is applicated.

• Nuclear Engineering and Technology
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• v.49 no.4
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• pp.865-872
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• 2017

For more than 10 years, the laser process has been studied for dismantling work; however, relatively few research works have addressed the effect of high-power fiber laser cutting for thick sections. Since in the nuclear sector, a significant quantity of thick material is required to be cut, this study aims to improve the reliability of laser cutting for such work and indicates guidelines to optimize the cutting procedure, in particular, nozzle combinations (standoff distance and focus position), to minimize waste material. The results obtained show the performance levels that can be reached with 10 kW fiber lasers, using which it is possible to obtain narrower kerfs than those found in published results obtained with other lasers. Nonetheless, fiber lasers appear to show the same effects as those of $CO_2$ and ND:YAG lasers. Thus, the main factor that affects the kerf width is the focal position, which means that minimum laser spot diameters are advised for smaller kerf widths.

• KEPCO Journal on Electric Power and Energy
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• v.8 no.2
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• pp.79-86
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• 2022

Recently, the amount of maintenance is increasing due to the aging of power facilities, but the budget is constrained. Therefore, the importance of asset management that selects replacement priorities based on the failure probability and enhances investment effects is increasing. Because the number of distribution transformers is very large, the proportion of investment cost is very high. Therefore, it is important to select the investment priority by evaluating the reliable remaining life based on the failure probability. This paper evaluates the statistical expected life using the failure data of distribution transformers for the last 11 years and the current operation data. The hazard rate of distribution transformer and MV cable was compared with each other and the adequacy of early failure removal was reviewed and the statistical expected life corresponding to the cumulative failure probability B3% was calculated.

• Journal of Korean Association for Spatial Structures
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• v.22 no.4
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• pp.71-79
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• 2022

Recently, the construction of tall buildings utilized by high strength-concrete in the whole world is tending to be on the rise. The application of high-rise structural system in buildings results in the excellent cut-down effect in construction materials due to section reduction. Therefore, in order to investigate the CO₂ and resource reduction effect for the high-rise structural system, comparisons of GWP and ADP in embodied energy of structural materlais between 4 type of high-rise structural system have been performed. As a result, GWP emission increased in the order of steel structure outrigger system, RC shear wall system, and RC outrigger system. On the other hand, ADP emissions increased in the order of RC shear wall system, RC outrigger system, and steel structure outrigger system.

• Journal of Agricultural Extension & Community Development
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• v.3 no.1
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• pp.1-16
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• 1996

The purpose of this study was to interpret the transformation of Cooperative Groups for Agricultural Production(CGAP) with the change of the Agricultural Productive Force. The specific objectives were; 1) To investigate the change of agricultural labour-power, 2) To investigate the change of agricultural mechanization and arable land, 3) To interpret the transformation and content of CLAP. The population of farmhouseholds has decreased continuously since the late 1960s. Especially, with the move-outs of youth ages of twenties to forties, the condition of agricultural labour-power has been more serious. The processing of agricultural mechanization was a small scale step in the 1970s, but after the 1980s there was a spread of middle-large machines. However the usage rate of agricultural machines was constrained by the bad conditions of arable land. From the 1970s to now, the CGAP have bean processed by many kinds of patterns. In the 1970s, the lack of labour-power caused the creation of the Co-Working Team. After the late of 1970s, the wage of agricultural employees was raised, because the working population of agriculture was cut down. Also, the induction of agricultural machine was promoted. As a result, in the 1980s, the Machine-Using Team occurred due to these conditions of agricultural productive force. In the late of 1980s, the population decreased more rapidly, and the use of large machines were spread. Than farmhouseholds laking labour-power gave a trust to other farmhouseholds and Teams which had machines. In 1990, Given-Trust Cooperations were enacted by law, and in order to overcome the lack of labour-power, and solve the problem of the successors of agriculture, Cooperative Organizations were also enacted by law. Finally, in Korea from the 1970s to now, as the agricultural productive force has barn changed, the Co-Working Team was transformed into the Machine-Using Team, and the Machine-Using Team was transformed into the Given-Trust Cooperation, and the Cooperative Organization.

• Horticultural Science & Technology
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• v.16 no.3
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• pp.370-373
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• 1998

Fumigation by combination of methyl bromide/phosphide ($MB/PH_3$) was much more effective in disinfestating the rose insect pests (Aphis gossypii, Tetranychus urticae, and Frankliniella occidentalis) than that by individual MB or $PH_3$. Fumigation for 2 hours in the chamber using ;$MB/PH_3$ at the concentration of $10/3g{\cdot}m^{-3}$ brought about 91.3% and 100% mortality in aphids and thrips, respectively. Fumigation for 3 hrs using ;$MB/PH_3$ at the concentration of 5/3 or $7/3g{\cdot}m^{-3}$ showed over 96% mortalities in mites and thrips as well as no phytotoxicity symptoms, e.g. tip burn or bent neck, in cut roses, while mortalities of mites and thrips were not influenced by increasing $CO_2$ concerntration from 0.03% to 10% or decreasing $O_2$ concentration up to 15% in fumigation chamber.

• Microbiology and Biotechnology Letters
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• v.32 no.4
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• pp.322-327
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• 2004

A strong constitutive PJH promoter from Bacillus sp. was applied to overexpress the endoxylanase gene (639 bp) in Bacillus subtilis. The expression plasmid, pJHKJ4, was designed to contain the $P_{JH}$ promoter and open reading frame of endoxylanase including its own promoter. The plasmid was introduced into B. subtilis DB431 and the resulting transformant was grown on LB glucose medium. At the end of cultivation, the endoxylanase activity in the culture supernatant reached about 140 DIm!. The enzyme in the supernatant was concentrated by ultrafiltration (MW cut-off 10 kDa and 30 kDa) and ammonium sulfate precipitation. For the concentration of the enzyme, ultrafiltration was more efficient than 70% ammonium sulfate precipitation. The stabilization of concentrated enzyme solution at $50^{\circ}C$ was examined with various stabilizers such as NaCI, glycerol, polyethylene glycol, sorbitol, and $CaCI_2$. The most effective stabilizers were found to be NaCI and $CaCI_2$.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.588-591
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• 2000

Serine palmitoyl transferase(SPT) and ceramidase are the key enzymes in sphingolipid biosynthesis. To study sphingolipid metabolism, we have got the 5'-upstream regions of human serine palmitoyl transferase subunit II and acid ceramidase gene by using GenomeWalker kits(Clontech Co.). Human genomic DNA was purified from HT29, human colon canser cell line by using DNAzol. We got several bands after secondary PCR and subcloned them to T7bule vector. Human SPTII promoter which we got was 2690bp but we cut it with Bgl II and vector with Bgl II and BamH I, and subcloned 1782bp to pGL2-enhancer vector and pGL2-basic vector with luciferase reporter gene. Human acid ceramidase promoter which we got were 2028bp and 1034bp and subcloned to pGL2-enhancer vector and pGL2-basic vector. We transfected these promoters to HT29 cell and assayed luciferase activity. For measuring transfection efficiency, pRL-TK vector with seapancy luciferase reproter gene was cotransfected with these promoters.

• Restorative Dentistry and Endodontics
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• v.22 no.2
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• pp.670-679
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• 1997

The pH changes in 4 small cavities prepared at the facial inner dentin and lingual outer dentin of the cervical and apical portion of root filled with calcium hydroxide pastes were investigated. Forty extracted permanent teeth with single canal were instrumented with step-back method, and then 4 small cavities were prepared. Two inner dentin cavities were cut a distance of about 1.0mm from the canal wall and two outer dentin cavities were cut to a depth of about 0.5mm from the root surface. Root canals and prepared cavities were flushed with 17% EDTA, and then irrigated with 5% NaOCl to remove smear layer. Teeth were randomly divided into four groups. Control group was not filled and the remaining other groups were filled with mixture of calcium hydroxide and distilled water, Vitapex$^{(R)}$ paste and Pulpdent$^{(R)}$ paste respectively. The pH change of the dentin in each cavity was measured at 0, 1, 3, 7, 14, 21, 28, 60, 90 days with pH microelectrode(WPI Co., USA). The results were as follows : 1. The groups obturated with Pulpdent$^{(R)}$ paste and Aqueous calcium hydroxide produced the increased pH level at 1 day and maintained plateau over next 3weeks and decreased after 3weeks. 2. The group obturated with Vitapex$^{(R)}$ paste observed no significant pH change until 2weeks and slight increased pH at 3weeks and sequential increasing after 3weeks. But, the pH in the group obturated with Vitapex$^{(R)}$ paste remained significantly below the pH measured in the other two experimental groups(P<0.05). 3. All experimental groups showed pH level similar to control group after 28 days. 4. The pH of outer dentin is slightly higher than that of inner dentin. There is no significant difference in pH level between apical and cervical dentin throughout the duration of the experiment, though apical dentin showed slightly higher pH than cervical dentin at 1 day(P<0.05).

• Applied Biological Chemistry
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• v.42 no.4
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• pp.288-292
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• 1999

It was previously reported that cobalt(II) effectively suppresses the postharvest gravitropic response of snapdragon (Antirrhinum majus L.) (Kim et al. (1997) Agric. Chem. and Biotechnol. 40, 567-571). In this study, several factors affecting the suppression of the gravitropic response by cobalt ion were examined. When flower stalks of snapdragon were pretreated with several different cobalt salts, cobalt nitrate turned out to be the most effective not only in reducing the response but also in preserving the flower quality. We also tested the effects of various detergents which were added to cobalt(II) solution, finding that Tween-40 was the best among the tested with respect to the effectiveness as well as the flower quality. Based on these results, we optimized a protocol for the chemical treatment; that is, a suppressor solution containing 10 mM $CO(NO_3)_2$ and 0.05% Tween-40 was directly sprayed on the gravitropically sensitive region of cut flowers of snapdragon. The suppressor treatment gave rise to a significantly improved results when the flower stalks were stored at a lower temperature after the chemical treatment.