• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.3
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• pp.1-7
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• 2018

As part of a research dedicated to the field evaluation of the durability of concrete subjected to freezing-thawing, this study analyzes the relationship between the surface roughness and the relative dynamic elastic modulus through image analysis. Four mix compositions with water-to-binder ratios (W/B) of 40%, 50%, 60% and 70% and without AE agent were considered to provoke early freezing. The basic physical properties of the mixes including the relative dynamic elastic modulus and the compressive strength were first evaluated experimentally according to W/B. Then, tests were performed to measure the surface roughness followed by photographs and SEM image analysis. The measured surface roughness tended to increase with larger number of freezing-thawing cycles regardless of W/B. The relative dynamic elastic modulus appeared to increase gradually with the number of cycles for the relatively denser mixes with W/B of 40% and 50%. Besides, the surface roughness increased only at rupture for the mixes with W/B of 60% and 70%. Moreover, the analysis of the photographs of the surface of the mixes with W/B of 40% and 50% revealed that the degradation progressed gradually from the surface with the freezing-thawing cycles. However, for the mixes with W/B of 60% and 70%, apparent change of the surface remained very insignificant until rupture at which damage like cracking could be observed. Consequently, the analysis of surface photograph or the measurement of the surface roughness presented some limitation in assessing the degree of freezing-thawing-induced degradation in case of relatively porous specimens. On the other hand, the photograph and surface roughness appeared to be sufficient for assessing such degradation for the mixes with W/B of 40% and 50%. Accordingly, the image of the surface and the surface roughness are potentially applicable on site for the assessment of freezing-thawing damages in relatively dense mixes.

• Journal of Korean Society of Forest Science
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• v.95 no.1
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• pp.102-112
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• 2006

The change of species composition and stand structure along altitudinal gradients in different aged stands was studied in five natural stands located each at 400 m, 800 m, 1,000 m, and two at 1,300 m above sea level (asl) in the western part of Mt. Chiri in Korea. Trees larger than 2.5 cm DBH were inventoried in 3 to 8 $20m{\times}20m$ quadrats in each study site. Stand ages were estimated based on the ages of Pinus densiflora Siebold & Zucc. and Abies koreana Wilson, and used to analyze the changes in species composition and stand structure including diameter and height distributions. Species composition was changed along altitudinal gradients as P. densiflora dominated stands at 400 m asl while A. koreana dominated stands at 1,300 m asl. Major species of Quercus also changed along altitudinal gradients as Quercus variabilis Blume at 400 m asl, Quercus serrata Thunb. ex Murray at 800 m asl, and Quercus mongolica Fisch. ex Ledeb. at higher than 1,000 m asl. The diameter distribution did not show significant differences among stands of different altitudes. However, the height distributions of upper crown layers were significantly different among stands at below and above 1,000 m as) (P < 0.0001). Trees taller than 20 m rarely appeared in stands over 1,000 m asl. P. densiflora dominant stands at 400 m asl developed two clumped age groups as one in 30-40 ages and the other around 70 years old. Q. serrata dominant stands at 800 m asl, Q. mongolica dominant stands at 1,300 m asl and A. koreana dominant stands at 1,300 m asl were estimated to be around 30, 70, and over 140 years old after major disturbances, respectively. The diameter distribution with age structure indicated that P. densiflora at 1,300 m asl might be replaced by Q. mongolica, and Q. mongolica might be replaced by A. koreana and Pinus koraiensis later. A. koreana dominant stand seemed to stay its dominance quite long if the large disturbance would be absent.

• Journal of Korean Society of Forest Science
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• v.40 no.1
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• pp.19-24
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• 1978

The study was conducted to find out the relationship between land cost and financial yield earned by the plantations of Pinus koraiensis, Pinus densiflora and Cryptomeria japonica, and to investigate possible land investment for the given rates of return. The result of the study could be summarized as follows: 1. In the case of Pinus koraiensis plantation on site index 12, the finnancial yield was 6.4 percent when the land cost was 0.5 million Won per hectare, but the yield was reduced to 2.1 percent when the cost was 2.5 million Won. It would be therefore necessary for inducing plantation investment to raise financial yield by control of forest land price. 2. The financial yield on land of zero expectation value, in other words, internal rate of return of land investment was estimated at 10 percent. If the opportunity cost of forest land is higher than this, the economic plantation is not visible even though the land is free. 3. With the expected financial yield of 3 percent, the possible land investment of poor sites was estimated at 1.24, 0.28 and 0.80 million Won per hectare for the plantation of Pinus koraiensis, Pinus densiflora and Cryptomeria japonica, respectively. In any case, however, land cost could not be over 3 million Won per hectare. 4. The rate earned from forest land investment was generally less than 10 percent. Therefore, the annual interest rate in forestry could not be higher than this, and hopeful rate is not exceeding 6 percent.

• Journal of Korean Society of Forest Science
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• v.69 no.1
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• pp.56-68
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• 1985

This study was conducted (1) to measure the nitrogen content of various parts of trees in a 24-year-old Pinus koraiensis plantation, providing a harvest method with the least impact on the self-serving mechanisms in the nitrogen status of the ecosystem and (2) to examine the seasonal changes in inorganic nitrogen (ammonium salt and nitrate, separately) at various soil depths and to study the self-serving mechanisms for nitrogen at the ecosystem, providing an appropriate method and season for the application of nitrogen fertilizers. The results obtained in this study were as follows; 1) Of the total nitrogen content of the total tree biomass (except for roots), nearly 61.5% was distributed in the needles, 20% in the branches, 5.5% in the stem bark, and 13% in the stem wood. Therefore, the harvest method of removing only wood parts for pulpwood production has little impact on the self-serving mechanisms of the site's nitrogen status. 2) Inorganic nitrogen concentrations decreased with increasing soil depths. The seasonal average concentration of inorganic nitrogen was highest in early spring and decreased in the following descending order; autumn, tollowed by mid-summer, and early summer. This pattern resulted from the fact that the loss of nitrate was greatly influenced by environmental factors. Thus, it was suggested that an application of active nitrogen fertilizer would be appropriate in spring.

• The Korean Journal of Physiology
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• v.18 no.2
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• pp.163-169
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• 1984

The effect of vanadate on the optimum pH of Na-K-ATPase was investigated. The results were as follows: 1) The optimum PH of Na-K-ATPase was shifted from PH 7.4 to 6.8 at 10 mM K by $5{\times}10^{-6}M$ vanadate. 2) The ratio of Na-K-ATPase activity at pH 6.8 and 7.4 increased with increasing vanadate concentration. 3) Inspite of the presence of $5{\times}10^{-6}M$ vanadate Na-K-ATPase activity at pH 7.4 was higher than that at pH 6.8 below 50 mM $Na^+$, and the ratio of Na-K-ATPase activity at pH 7,4 and 6.8 was higher than that of the control. 4) Na-K-ATPase activity at pH 7.4 was higher than that at pH 6.8 below 7mM $K^+$. 5) Optimum pH of Na-K-ATPase activity was shifted from pH 7.4 to 6.8 by $10^{-5}M$ vanadate at 5 mM $K^+$. 6) $K^+$-pNPPase activity increased with lowering of pH, and the degree of inhibition of $K^+$-pNPPase activity by $10^{-7}$M vanadate was decreased with lowering of pH. These results suggest that vanadate shifts the optimum pH of Na-K-ATPase activity to more acidic PH than PH 7.4. This effect may not be caused by the decrease in the inhibitory potency of vanadate itself to Na-K-ATPase by the change of medium pH, but mainly by the alteration of Na-and K-binding site, which appears in the presence of vanadate only.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.2
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• pp.327-335
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• 2018

In order to calculate the quality management cost of construction work, the process must conform to relevant laws and regulations. In details, the cost of the various items such as quality test fee and quality control activity cost are required to be calculated. Regarding the quality management costs, the labor cost is applied to the quality examination fee and the calculation unit quantity in the construction quality management duties. The application of the unit price of the labor cost stipulates that Construction Association of Korea and Korea Engineering & Consulting Association apply the unit price which is surveyed and published. However, in the related laws and regulations, the standard of the quality manager and quality tester is not clear. This accounts for the confusion in the cost of construction management and the cost of labor. In the current law, the allocation standard of quality control personnel is specified according to the size of the construction, but the standard of placement of quality testers is not specified. At the construction site, there is no assignment criteria manpower for quality testers except quality managers, or very little work is being done. The quality control personnel conducts the quality test work to be carried out by the quality tester, and this carrying out heavy work. Therefore, it is difficult to maintain quality control activities. In this study, the labor cost of quality management expenses and the allocation criteria of quality managers and quality testers are established and presented for the purpose of securing the quality of the construction work and preventing the construction work. It is stipulated that the standards of the relevant laws and regulations, which are not clear, should be classified into quality control personnel and quality testers according to the size of the construction. Based on the unit price of Korea Engineering & Consulting Association, the personnel expenses of quality managers and quality testers are proposed to apply the unit price of engineer (professional engineer, specialist, advanced, intermediate, beginner) and skilled technicians (advanced, intermediate, beginner).

• Journal of the Korean Geographical Society
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• v.31 no.3
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• pp.489-507
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• 1996

The purpose of this study is to examine the increasing number of unregistered manufacturing plants and related problems, and to recommend alternative solutions to the problems. Data are obtained from a field survey of randomly selected small scale manufacturing plants in Seoul and its suburban cities. A total number or respondents are 533, and 416 of them are unregistered plants. The Capital Regional Planning has had a goal during last three decades to lead a balanced regional economic development by restriction manufacturing plants in the Capital Region and by encouraging them in other regions in the nation. It was 1984 when a comprehensive planning was established to achieve this goal. Sets of various regulations, by-laws and codes have been implemented to regulate manu-facturing activities in the Capital Region to achieve the goal. The region is divided into three sub-regions, and a different degree of regulations is applied to each sub-region. Only a certain types of industries are allowed in a particular sub-region. For instance, a plant manufacturing high-technology products could be allowed in the most urbanized sub-region. All manu-facturing plant in the Capital Region which has ares size of larger than 200"\;"$m^2$ is compulsory to register to the local government office. In practice, however, it is not common or sometimes almost impossible to get approval for many applicant manufacturers because of strict regulations. There have been increasing number of plants in the Capital Region during last several decades, despite the strict regulations. Many of those newly established plants are without formal registration at the local administration office. howerver. These are so called 'unregisterd' plants. Surveyed data and many government official data show that many of unregistered plants have been established in recent years. which indicate that current regulations are no longer effective. The number of unregistered plants are increasing tin the Capital Region because of many locational advantages in the region for plants, particularly those in small scale. Unregistered plants are the source of many problems, such as local water pollution or noise pollution in residential areas. There are also many administration problems, bed\cause they are not registered. The central government has attempted to cure the problems of unregistered plants. For example, the government allowed a unregistered plant to remain at present site for three ydars, if it met certain conditions in three years. However, this program was unsuccessful because many of those plants were not able to meet the concitions. Three times the government renewed the term for those which did not meet conditions since 1989, but it was afraid to be without success. There are many evidences that current policies to control manufacturing plants are not effective. The Capital Region must face mounting problems if ploicies are not reformed soon. This study suggests that the policy of the Capital Regional Planning has to be reoriented to provide more favorable policies for manufacturing plants in the Capital Region than current regulations which is aimed to restrict manufacturing activities. It is time to improve many existing problems in the region through reforms and of current regulations to foster unregistered plants. This study also proposes many smaller-area sub-divisions instead of current three large area sub-regions which is too broad to apply single kind of regulation, or codes. Flexible regulations and codes can be applied to such a small-area sub-divivisions based on location and industrial characteristics of the individual sub-divisions. It is necessary to provide decent industrial environment in the Capital Region, which is best equipped to provide many favorable industrial locational factors in the nation, thus this nation can be further prepared to compete in an inter-national market at an era of globalization in manufacturing.

• Journal of Periodontal and Implant Science
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• v.29 no.4
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• pp.979-995
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• 1999

This study was investigated to observe the effect of Treponema denticola cell sonicates(TDC) and Treponema lecithinolyticum cell sonicates(TLC) on cytokine secretion and matix metalloproteinase-2(MMP-2) activation of cultured human gingival fibroblast. Several experiments were performed including $IL-1{\beta}$, IL-6 ELISA for the effect on the $IL-1{\beta}$, IL-6 secretion of human gingival fibroblast. Also gelatinase zymography and gelatin dissolubility test for the activation of MMP-2 secreted by gingival fibroblast. The results were as follows. 1. The effect of TDC and TLC on IL-6 secretion of human gingival fibroblast showed statistically significant increase of IL-6 secretion in the TDC and TLC treated group compared to no treatment group(p<0.05) . 2. The amount of $IL-1{\beta}$ secretion was below the lower limit and there was no difference in the $IL-1{\beta}$ secretion of gingival fibroblast between TDC, TLC treated group and no treatment group. 3. The active form of pro MMP-2 with 72 kDa molecular weight was activated in both TDC and TLC treated group and clear band was appeared at 62kDa site on the zymography. 4. Gelatin dissolubility of MMP-2 secreted by gingival fibroblast was higher in TDC and TLC treated group compared to no treatment group(p<0.05). 5. In the TDC treated group, serine protease of T. denticola affect gelatin dissolubility. But in the TLC treated group gelatin was degraded by only MMP secreted by gingival fibroblast. Regarding to the above results, TDC and TLC have an effect on the IL-6 secretion increase of human gingival fibroblast and appears to activate pro MMP-2 which degrades collagen.

• Microbiology and Biotechnology Letters
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• v.41 no.1
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• pp.17-25
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• 2013

The thermotolerant methylotrophic yeast Hansenula polymorpha is an attractive model organism for various fundamental studies, such as the genetic control of enzymes involved in methanol metabolism, peroxisome biogenesis, nitrate assimilation, and resistance to heavy metals and oxidative stresses. In addition, H. polymorpha has been highlighted as a promising recombinant protein expression host, especially due to the availability of strong and tightly regulatable promoters. In this study, we investigated the possibility of employing human serum albumin (HSA) as the fusion tag for the secretory expression of heterologous proteins in H. polymorpha. A set of four expression cassettes, which contained the methanol oxidase (MOX) promoter, translational HSA fusion tag, and the terminator of MOX, were constructed. The expression cassettes were also designed to contain sequences for accessory elements including His8-tag, $2{\times}(Gly_4Ser_1)$ linkers, tobacco etch virus protease recognition sites (Tev), multi-cloning sites, and strep-tags. To determine the effects of the size of the HSA fusion tag on the secretory expression of the target protein, each cassette contained the HSA gene fragment truncated at a specific position based on its domain structure. By using the Green fluorescence protein gene as the reporter, the properties of each expression cassette were compared in various conditions. Our results suggest that the translational HSA fusion tag is an efficient tool for the secretory expression of recombinant proteins in H. polymorpha.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.4
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• pp.425-437
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• 2007

Flow distribution of water and sedimentation rate were investigated to understand the hydrodynamics and settling characteristics of particulate materials in a constructed wetland for treatment of non-point sources pollutants, the Sihwa constructed wetland, Korea. The Sihwa constructed wetland is divided into three sub-wetlands(the Banwol, the Donghwa and the Samhwa wetlands) to treat the polluted water from three streams, the Banwol stream, the Donghwa stream and the Samhwa stream. From the results of water flow experiment using dye(Rhodamine 50WT Red), it was found that the water flow in the wetland was prevailing at the waterway and open water. Dye was spread slowly in the closed water area planted by plants. The mean hydraulic retention time(HRT) at the upper area of high wetland and lower wetland of Banwol, was found to be 34.1 hr at the upper area and 74.6 hr at the lower area respectively, totaling approximately 108.7 hr(4.5 days). The sedimentation rate was higher at lower area(sites of B, C and D) of the wetland than upper area(site of A which is settling zone). Based on the forecast for 20 years as to the amount of sediment that can be deposited in the open water in the future, the sediment depth of each area would be like this: A: 6.3 cm, B: 8.3 cm, C: 7.0 cm, D: 9.5 cm. The contents of organic materials in the sediment deposited within the sediment trap were found to be higher overly in the first investigation period which had much rainfall, and B, C and D areas were found to have an increased COD accumulation than A area. Also, nitrogen and phosphorus were found to increase in the down-stream of the wetland. The results of this study suggest that a sustainable research and management for the characteristics of water flow pattern and sedimentation changeable as time passes is needs to maintain or improve the efficiency of water treatment in the constructed wetland.