• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.7
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• pp.973-979
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• 2005

To investigate the effect of Pinus densiflora on biochemical parameters in type I diabetic rats, we evaluated the changes of body weight, fasting blood glucose level, oral glucose tolerance test (OGTT) and biochemical parameters after the intraperitoneal injection of distilled solution of Pinus densiflora in streptozotocin (STZ)­induced rats. Thirty-seven male Sprague Dawley rats $(180\pm10g)$ were divided into four groups; diabetic mellitus (DM) group received STZ (50 mg/kg BW, i.v.); low level of pine extract (LP) group received Pinus densiflora (5 mg/kg BW, i.p.), high level of pine extract (HP) group received Pinus densiflora (10 mg/kg BW, i.p.) after the single injection of STZ (50 mg/kg BW, i.v.), respectively. Normal control (NC) group received saline. The change of fasting blood glucose level and OGTT were measured using glucocard II, and the change of biochemical parameter were measured by Automatic Chemistry Analyzer (Hitach-747, Japan). Mean body weight change of DM group was retarded greatly by STZ-exposure. While, body weights of LP and HP groups were progressively increased with some fluctuation, although the increase rates were slower than that of NC group. Fasting blood glucose levels of LP and HP groups were reduced by Pinus densiflora injection, although the fasting blood glucose levels were higher than that of NC group. The results of OGTT was significantly improved in both of LP and HP group compared to DM group. Increases of blood glucose, alanine aminotransferase (ALT), alkaline phosphatase (ALP) and blood urea nitrogen (BUN) levels by STZ-exposure were attenuated by the Pinus densiflora treatment (p<0.05). From the results, it was suggested that Pinus densiflora has a tendency to decrease STZ-induced toxicity in terms of monitoring fasting blood glucose, OGTT and some biochemical parameters of rat.

• Journal of the Korean Institute of Landscape Architecture
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• v.35 no.5
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• pp.46-55
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• 2007

This study was carried out to analyze both the root structure and the fine root phytomass of the vertical and horizontal distribution of Zelkova serrata Makino. which was transplanted in the reclaimed land from the sea in Gwangyang, Jeonnam, South Korea. The base ground was reclaimed land from the sea. $Z_1$ of the planting ground was filled to a $100{\sim}150cm$ thickness with the improved soil instead of the reclaimed soil from the sea, $Z_2$ of the planting ground was covered to a $20{\sim}30cm$ thickness with the improved soil and $Z_3$ of the planting ground was mounded to 120cm thickness with the improved soil on the reclaimed land from the sea. In addition, $Z_4,\;Z_5\;and\;Z_6$ of the planting grounds were at the large-sized mound on the reclaimed land from the sea. $Z_4$ of the planting ground was located at the lowest level, $Z_5$ planting ground was located at the slope and $Z_6$ planting ground was located at the top of the large-sized mound. The large-sized mounds contain 3 layers, the base layer was reclaimed land from the sea and the second layer was mounded to a $200{\sim}300cm$ thickness with the desalinized soil from the sea on the base layers and the finally layers were mounded to a $80{\sim}120cm$ thickness with improved soil on the second layer. The planting grounds $Z_3,\;Z_4,\;Z_5\;and\;Z_6$ developed roots such as tap roots, lateral roots and heart roots. However, in $Z_1\;and\;Z_2$ roots development were inhibited. The fine-root phytomass of the 6 planting ground types was as follows: $113.5g\;DM/m^2$ for $Z_5$, $105.5g\;DM/m^2$ for $Z_4$, $88.3g\;DM/m^2$ for $Z_3$, $81.0g\;DM/m^2$ for $Z_6$, $73.0g\;DM/m^2$ for $Z_2$, $43.3g\;DM/m^2$ for $Z_1$. The vertical distribution of the fine root phytomass decreased from the upper to the deeper soil profiles in the 6 mound types. The fine root phytomass was $43.3{\sim}71.8%$ in a $0{\sim}20cm$ thickness of soil layer and it decreased according to the distance from the nearest trees. The root growth in the improved soil was better than in the reclaimed soil from the sea. However, root growth decreased more in the disturbed soils even though the planting grounds contained the improved soils. The retarded development of roots and the spatial distribution patterns of the fine root phytomass were closely connected to the reclaimed soil from the sea. In the disturbed soil, the soil hardness and alkalic cation($Na^+,\;K^+,\;Ca^{2+},\;Mg^{2+}$). were high and the soil water was lacking. We suggest that the construction of planting grounds and the improvement of bad soil are necessary for the proper and effective growth of landscaping plants.

• Management & Information Systems Review
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• v.36 no.3
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• pp.131-150
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• 2017

The purpose of this study is to observe the spread pattern of open source software (OSS) while establishing relations with surrounding actors during its operation period. In order to investigate the change pattern of participants in the OSS, we use a netnography on the basis of online data, which can trace the change patterns of the OSS depending on the passage of time. For this, the cases of three OSSs (e.g. jQuery, MooTools, and YUI), which are JavaScript frameworks, were compared, and the corresponding data were collected from the open application programming interface (API) of GitHub as well as blog and web searches. This research utilizes the translation process of the actor-network theory to categorize the stages of the change patterns on the OSS translation process. In the project commencement stage, we identified the type of three different OSS-related actors and defined associated relationships among them. The period, when a master commences a project at first, is refined through the course for the maintenance of source codes with persons concerned (i.e. project growth stage). Thereafter, the period when the users have gone through the observation and learning period by being exposed to promotion activities and codes usage respectively, and becoming to active participants, is regarded as the 'leap of participants' stage. Our results emphasize the importance of promotion processes in participants' selection of the OSS for participation and confirm the crowding-out effect that the rapid speed of OSS development retarded the emergence of participants.

• Korean Journal of Agricultural Science
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• v.22 no.1
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• pp.1-10
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• 1995

All agricultural crops and products should be cultured, harvested, handled and processed by the proper mechanical methods in the mechanized farming systems. Agricultural crops might be injured or deformed through various working stages due to static or dynamic forces of machines. Mechanical forces had to be applied with proper degrees to the agricultural crops in incoincidence with properties of crops without any damage of crops so as to increase the work efficiency qualitatively. Knowledges of mechanical properties of agricultural materials are essential to prevent of agricultural crops in relation with mechanical farming system. This study was carried out to examine and analyze the creep behavior of the rice stalk on growing and harvesting periods by mechanical model with computer measurement system in radial directional compressive force and bending force. The creep behavior of the rice stalk could be predicted precisely and its results approached closely to the measured values. The creep behaviors were increased greatly with increase of compressive force, namely, the steady state creep behavior occurred at the force less then 25N and the logarithmic creep behavior at the force bigger than 30N. The instantaneous elastic modulus $E_o$ and the retardation time ${\tau}_K$ were increased together with increase of applied forces, meanwhile the retarded elastic modulus $E_r$ and viscosity ${\eta}_v$ were decreased with increase of applied forces in mechanical model being expected the creep behavior in relation with the level of applied forces, which was well explained that the rice stalk might be visvo-elastic material. In the creep test along the stalk portion with compressive force and bending force, the intermediate portion showed greatest values and also the lower portion showed the least values, which implied that the intermediate portions of rice stalk were very weak. The steady state creep behavior occured at the intermediate portion and the upper portion in the rice stalk at the compressive force larger than 25.0N, which showed the possibility of injury due to external forces.

• Korean Journal of Plant Resources
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• v.25 no.1
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• pp.156-168
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• 2012

Chrysanthemum is a cut flower species that normally lasts for 1 to 2 weeks, in some cases 3-4 weeks. This has been attributed to low ethylene production during senescence. Reduction in cut flower quality has been attributed to the formation of air embolisms that partially or completely blocks the water transport from the vase solution to the rest of the cut flower stem, increasing hydraulic resistance which may cause severe water stress, yellowing, wilting of leaf, and chlorophyll degradation. Standard type chrysanthemum can be harvested when buds were still tightly closed and then fully opened with the simple bud-opening solution. Standard type chrysanthemum can also be harvested when the minimum size of the inflorescence is about 5-6 cm bud which opened into the first flower full-sized flower. While spray varieties can be harvested when 2-4 most mature flowers have opened (40% opening). Cut flowers are sorted by stem length, weight, condition, and so on. Standard chrysanthemum is 80 cm length for standard type and 70cm for spray type. Pre-treatment with a STS, plant regulator such as GA, BA, 1-MCP, chrysal, germicide, and sucrose, significantly improved the vase life and quality of cut flowers. It is well established that vase solutions containing sugar can improve the vase life of cut chrysanthemum. Chrysanthemum is normally packed in standard horizontal fiberboard boxes. Chrysanthemum should normally be stored at $5{\sim}7^{\circ}C$. Precooling resulted in reduction in respiration, decomposition, and transpiration activities as well as decoloration retardation. There was significant difference between "wet" storage in 3 weeks and "dry" storage in 2 weeks. In separate pulsing solution trials, various germicides were tested, as well as PGRs to maintain the green color of leaves and turgidity. Prolonging vase life was attained with the application of optimal solution such as HQS, $AgNO_3$, GA, BA and sucrose. This also retarded senescence in leaves of cut flower stems. Fresh cut chrysanthemum can be transported using a refrigerated van with $5{\sim}7^{\circ}C$. Increasing consumption and usage of cut chrysanthemum of various cultivars would require efficient transport system, and effective information exchange among producer, wholesaler, and consumer.

• Korean Journal of Food Science and Technology
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• v.11 no.1
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• pp.42-49
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• 1979

In order to evaluate the utility of the anthocyanins of Amaranthys tricolor L. as an edible pigment, the present study was undertaken to investigate the effects of pH. temperature, ascorbic acid, sugars and their degradation products, quercetin, thiourea, sodium pyrophosphate and metal ions on the stability of the anthocyanins in the model systems. The results obtained from this study were as follows. 1. The degradation of total anthocyanins was retarded as the pH levels decreased from 8.0 to 1.0. At pH 1.0, however. the initial degradation reaction proceeded faster than at pH 2.0 to 3.0 2. On heating in buffered aqueous solution at $80^{\circ}C$, the total anthocyanin content was higher at pH 2.0 than other pH levels. Increasing the storage temperature accelerated greatly the pigment degradation. In darkness at $40^{\circ}C$, after 10 days, only 19% of the original amount was left, while at $2^{\circ}C$, under the same conditions of storage, approximately 90% of the pigment was retained. The half-life of the pigment, 63.0 days at $2^{\circ}C$, shortened to 1. 7 days at $40^{\circ}C$. 3. An increase in ascorbic arid concentration from 0. 15 to 0.50 mg/ml lowered the anthocyanin retention. 4. There was no significant difference between glucose and fructose in anthocyanin degradation effect. Furfural was more effective than other sugar degradation products, formic acid or levulinic acid in accelerating anthocyanin breakdown. 5. Neither quercetin nor sodium pyrophosphate had a protective effect on the anthocyanins in the presence of ascorbic acid, while, in the systems 0.5 or 1 mg/ml of thiourea with $150{\;}{\mu}g/ml$ of ascorbic acid, the loss of anthocyanins was significantly reduced. 6. Both mercuric and cupric ions in 30 ppm greatly accelerated anthocyanin degradation.

• The Korean Journal of Ecology
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• v.26 no.3
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• pp.143-150
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• 2003

Korea has plentiful precipitation but rainfall events concentrate on several months of rainy season in her weather condition. Korea, therefore, experiences drought for a given period every year. Moreover the soil has usually low water holding capacity, as it is composed coarse particles originated from the granite. Response of several oaks and the Korean red pine (Pinus densiflora) on water stress showed that water budget was significant factor determining vegetation distribution. In addition, dehydration level due to cold resistance mechanism of several evergreen plants during the winter season was closely related to their distribution in natural condition. Experimental result under water stress showed that the Korean red pine was very tolerant to desiccation but the seedlings showed high mortality during the dry season. The mortality tended to proportionate to soil moisture content of each site. A comparison between soil moisture content during June when it is severe dry season and moisture content of the culture soil when the pine seedlings reached the permanent wilting point due to water withheld proved that high mortality during the dry season was due to water deficit. Water potential of sample plants measured during the exposure experiment to the air pollutant showed a probability that water related factors would dominate the occurrence of visible damage and the tolerance level of sample plants. In both field survey and laboratory experiment, plants exposed to air pollution showed more rapid transpiration than those grown in the unpolluted condition. The result would due to injury of leaf surface by air pollutants. Aluminum (Al/sup 3+/) increased in the acid soil not only inhibits root growth but also leads to abnormal distribution of root system and thereby caused water stress. The water stresses due to air pollution and soil acidification showed a possibility that they play dominating roles in inducing forest decline additionally to the existing water deficit due to weather and soil conditions in Korea. Sludge, which can contribute to improve field capacity, as it is almost composed of organic matter, showed an effect ameliorating the retarded growth of plant in the acidified soil. The effect was not less than that of dolomite known in widely as such a soil ameliorator. Litter extract contributed also to mitigate the water stress due to toxic Al/sup 3+/. We prepared a model showing the potential interaction of multiple stresses, which can cause forest decline in Korea by synthesizing those results. Furthermore, we suggested restoration plans, which can mitigate such forest decline in terms of soil amelioration and vegetation restoration.

• Journal of the Korea Institute of Building Construction
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• v.9 no.4
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• pp.55-61
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• 2009

Recently, the number of high-rise buildings being built in Korea by major construction companies for residential and commercial use has been increasing. When constructing a high-rise building, it is necessary to apply massive amounts of concrete to form a mat foundation that can withstand the huge load of the upper structure. However, it is of increasing concern that due to limitations in terms of the amount of placing equipment, available job-sites and systems for mass concrete placement in the construction field, it is not always possible to place a great quantity of concrete simultaneously in a large-scale mat foundation, and for this reason consistency between placement lift cannot be secured. In addition, a mat foundation Is likely to crack due to the stress caused by differences inhydration heat generation time. To derive a solution for these problems, this study provides test results of a hydration heat crack reduction method by applying placement lift change and setting time control with a super retarding agent for mass concrete in a large-scale mat foundation. Mock-up specimens with different mixtures and placement liftswere prepared at the job-site of a newly-constructed high-rise building. The test results show that slump flow of concrete before and after adding the super retarding agent somewhat Increases as the target retarding time gets longer, while the air content shows no great difference. The setting time was observed to be retarded as the target retarding time gets longer. As the target retarding time gets longer, compressive strength appears to be decreased at an early stage, but as time goes by, compressive strength gets higher, and the compressive strength at 28 days becomes equal or higher to that of plain concrete without a super retarding agent. For the effect of placement lift change and super retarding agent on the reduction of hydration heat, the application of 2 and 4 placement lifts and a super retarding agent makes it possible to secure consistency and reduce temperature difference between placement lifts, while also extending the time to reach peak temperature. This implies that the possibility of thermal crack induced by hydration heat is reduced. The best results are shown in the case of applying 4 placement lifts.

• 대한공업교육학회지
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• v.39 no.1
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• pp.189-208
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• 2014

The purpose of this research was to investigate the critical issues and practical strategies that Korean technology teachers perceived. To accomplish the purpose of this study, a qualitative study was conducted to identify critical issues and practical strategies of Korean technology education targeted on Korean technology teachers. A purposeful sampling for choosing technology teachers was used for this study with three selection conditions: 1) 'Excellent Korean technology teacher' award winning teachers, or 2) technology teachers actively involved in both on-line and off-line teachers' association, and 3) leaders in local technology teachers' association. This study conducted exploratory in-depth interviews with selective 15 technology teachers regarding critical issues and practical strategies of Korean technology teachers. The interpretation of the interview content was conducted by two researchers using the thematic analysis which analyzed the frequency of concepts, words, and meanings held from collected data. In the conclusion, critical issues researchers identified were 1) curriculum problems, 2) education environment and facilities problems, 3) teachers' problems, 4) students' problems, 5) related research institution and college problems, 6) social problems. Secondly, Korean technology teachers agreed with following practical strategies 1) separating technology education from home economic education, 2) sharing practices on managing and improving educational environment and laboratory for technology education, 3) actively involving in technology teachers' group, 4) motivating students using hands-on activity 5) improving the quality and the quantity on technology teachers preparatory institution, 6) advertising the values of technology education to the public. Lastly, the positive factors to succeed technology education were 1) technology education satisfying social needs and 2) technology teachers' will or passion toward improving their technology classrooms. The negative factors to hinder technology education were 1) low self-respect of Korean technology teachers and 2) rejection or retarded acceptance toward social transition. Several recommendations based the conclusion were suggested as 1) implementing supplementary study toward selected critical issues and 2) conducting exemplary case studies regarding concrete practical strategies for improving challenges of Korean technology education.

• Korean Journal of Weed Science
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• v.8 no.1
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• pp.71-89
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• 1988

This study was conducted to evaluate the effect of a growth retardant, Paclobutrazol on the growth, yield and its components. and physiological traits in peanut cv. Saeddle (early variety) and Nampung (medium variety). The results are summarized as follows : Main stem and branch length of both varieties were remarkably retarded at early growth stage application, but the retardation effect was reduced at late growth stage application. Number of branches was increased remarkably by treating 60ppm at 20days after seedling (DAS) in early variety. Lodging ill medium variety was not observed through growth period when 120ppm of Paclobutrazol was applied while lodging was not appeared between 40 DAS and 80 DAS in early variety. The numbers of riped pods in early variety was increased when application of 120ppm at 40 DAS was made while it was increased as application of 120ppm at 90 DAS in the medium variety. Cercospora leaf spot was reduced by spraying at 40 or 50 DAS regardless of concentration and varieties. Chlorophyll content and photosynthetic activity increased when paclobutrazol was applied during 40-60 DAS in early variety while these were observed at 90 DAS in medium variety. Seed weight tended to increase as paclobutrazol application was delayed. The ratio of pods to seeds was higher at 60ppm-40 DAS in early variety while it was higher at 120ppm-90 DAS in medium variety.