• Korean Journal of Soil Science and Fertilizer
• /
• v.11 no.3
• /
• pp.127-144
• /
• 1979

Recent trend in the studies on the forming processes, chemical characteristics and chemical structure of humic substances with some discussions are reviewed and some arguments for the elucidation of the chemical structure of humic substances are summarized.

• Journal of the Korean GEO-environmental Society
• /
• v.17 no.11
• /
• pp.35-43
• /
• 2016

In this study, by using a Effective Microorganisms Brewing Cycle, it confirmed the purification effect of pollutants that are adsorbed on the basins stench removal and retarding soil. On the basis of on-site application test, a soil decontamination system will be suggested. Using a Effective Microorganisms Brewing Cycle, the odor concentration is reduced 2.5 times than that of natural purification treatment method. It was measured and found that the quality of the pore water discharged from the soil is improved. In addition, it was found that a composite of copper and lead with the fermentation microorganisms adsorbed on soil particles from the surface of the stirred experiments lagoon mixed soil is reduced to 65% and 66%, respectively, The TPH organic component was confirmed that the reduction effect of 85%. Restoration of reservoir contaminated soils using the effective microorganism brewing cycle needs to be more developed and implemented as a long-term purification system. This study may be a good reference of developing more complete microorganism brewing system which will efficiently reduce the odor and soil contamination based on optimal stirring and mixing ratio of the compound solutions and contaminated soils in reservoir.

• Korean Journal of Environmental Biology
• /
• v.17 no.2
• /
• pp.129-138
• /
• 1999

Chlorinated aromatic compounds are one of the largest groups of environmental pollutants as a result of world-wide distribution by using them as herbicides, insecticides, fungicides, solvents, hydraulic and heat transfer fluids, plasticizers, and intermediates for chemical synthesis. Because of their toxicity, persistence, and bioaccumulation, the compounds contaminated ubiquitously in the biosphere has attracted public concerns in terms of serious influences to wild lives and a human being, such as carcinogenicity, mutagenicity, and disturbance in endocrine systems. The biological recalcitrance of the compounds is caused by the number, type, and position of the chlorine substituents as well as by their aromatic structures. In general, the carbon-halogen bonds increase the recalcitrance by increasing electronegativity of the substituent, so that the dechlorination of the compounds is focused as an important mechanism for biodegradation of chlorinated aromatics, along with the cleavage of aromatic rings. The removal of the chlorine substituents has been known as a key step for degradation of chlorinated aromatic compounds under aerobic condition. This can occur as an initial step via oxygenolytic, reductive, and hydrolytic mechanisms. The studies on the biochemistry and genetics about microbial dechlorination give us the potential informations for microbial degradation of xenobiotics contaminated in natural microcosms. Such investigations might provide biotechnological approaches to solve the environmental contamination, such as designing effective bioremediation systems using genetically engineered microorganisms.

• Korean Journal of Environmental Agriculture
• /
• v.30 no.2
• /
• pp.209-215
• /
• 2011

BACKGROUND: The paddy ecosystem is periodically disturbed with a relatively consistent cycle in short term. However, in long term aspect, the paddy as habitats of organisms has been affected by the change in farming practices. Accordingly, the composition and their densities of fauna species inhabiting the wet paddy has been changed. The geological distribution of a species is very helpful to understand the past and current status of habitats and biodiversity. METHODS AND RESULTS: We monitored 290 sites of open plain paddy or terraced valley paddy located in 138 cities or counties of South Korea and analyzed examine geological distribution of a taxon of freshwater invertebrates, diving beetles (Dytiscidae) which inhabited the paddy ecosystem. This survey was conducted from 2005 through 2007. The total species of diving beetles found in the paddy were identified to be 15 genus 26 species among the family of Dytiscidae. Among them, 24 species were found in the terraced valleys-in paddy fields, and 19 species were found in the open plain paddy fields. Eleven species of them were rarely found in the paddy. The average body size of the adult diving beetles of each species was between 2.0 and 35.0 mm. Most of the diving beetle species except for 11 species with rare frequency of occurrence were found in almost all sites of the terraced valley paddy fields but three species (Agabus browni, Agabus japnicus, and Ilybius apicalis) were not found in the open plain paddy fields. The species distributed relatively widely over some sites of the open plain paddy fields were Guignotus japonicus, and Rhantus pulverosus. Specifically, Ilybius apicalis was found in a specific region, the east-southern part of Korean peninsula, whereas Coelambus chinensis was found only in valley paddy field of the region where Ilybius apicalis was not found. Overall distribution range of diving beetles in open plain paddy fields was limited to few area than in terraced valley paddy fields. CONCLUSION(s): The differences in the range of distribution of diving beetles between terraced valley paddy fields and open plain paddy fields was thought to be the result of an complex action of physico-chemical environments such as annual water status and the degree of chemical application involving differences in the extent of disturbance of the paddy ecosystem, the connectivity of the paddy to an adjacent biotope, and interrelationships among competitors.

• Management & Information Systems Review
• /
• v.31 no.3
• /
• pp.223-248
• /
• 2012

This study analyses support policy and structural change of textile industry in Daegu Kyungbuk region, and suggests major issues for textile industry's innovation. In Daegu Kyungbuk, it was 1999 that a policy, so called Milano Project, in order to promote a textile industry was devised. In 2004, the Regional Industrial Promotion Plan was devised. The plan was born from a view point of establishing a regional innovation system and of promoting the innovative clusters under a knowledge based economy. After then, the Regional Industry Promotion Project or Regional Strategic Industry Promotion Project became a core of regional textile industrial policy. Research results indicated that the first stage Milano project (1999-2003) showed both positive and negative effects. There were no long-term development plan, clear vision and strategy. But, core industrial infrastructure for differentiated product development, such as New product Development Support Center and Dyeing Design Practical Application Center, was constructed. The second stage Daegu Textile Industry Promotion Plan (2004-2008) displayed a significant technological performance and new product sales with the assistance of Kyungbuk province. Also, textile industry revealed positive fruits such as financial structure, productivity, and profitability as a result of strong restructuring. In industrial structure, there was a important change from clothe textile material to industry textile material. Most of textile companies did not showed high capability in CEO's technology innovation intention, entrepreneurship, R&D and human resource competency in compare with other industry. We suggested that Daegu Kyungbuk has to select and concentrate on the high-tech textile material and living textile for sustainable development and competitiveness. We also proposed a confidence and cooperation based innovation network and company oriented innovation cluster.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.43 no.10
• /
• pp.1594-1606
• /
• 2014

The purpose of this study was to examine safety accidents related to school foodservice, working and operating environments of school foodservice, status and awareness of safety education, educational needs, and information on qualitative improvement of school foodservice. The subjects in this study were 234 cooks in charge of cooking at elementary and secondary schools in Chungbuk. A survey was conducted from July 30 to August 8, 2012, and among 202 questionnaires gathered, 194 completed questionnaires were analyzed. Statistical analyses were performed on data utilizing the SPSS version 19.0. The main results of this study were as follows: 44.3% of workers experienced safety accidents. The most frequent safety accident was 'once' (60.5%), and most safety accidents took place between June and August (31.4%). The time at which most safety accidents happened was between 8 and 11 am. Most safety accidents happened during cooking (52.3%) and while using a soup pot or frying pot (52.4%). The most common accidents were 'burns', 'wrist and arm pain', and 'slips and falls'. Respondents who experienced safety accidents replied that 57.6% of employees dealt with injuries at their own expense, and only 35.3% utilized industrial accident insurance. In terms of the operating environment, the score for 'offering information and application' was highest (3.76 points), whereas that for 'security of budget' was lowest (1.77 points). As for accident education, employees received safety education approximately 3.45 times and 5.10 hours per year. Improving the working environment of school foodservice cooks requires administrative and financial support. Furthermore, educational materials and guidelines based on the working environment and safety accident status of school foodservice cooks are required in order to minimize potential risk factors and control safety accidents in school foodservice.

• Korean Journal of Ecology and Environment
• /
• v.48 no.4
• /
• pp.219-228
• /
• 2015

To secure water resources, dams are normally constructed on the upper - middle part of streams, and it generates physical disturbances such as habitat alteration and stream fragmentation. Such construction can restrict movement of aquatic organisms, especially for freshwater fish which is one of top predator in aquatic ecosystem, and cause genetic fragmentation and community change. In this study, to investigate impact of habitat alteration after dam construction on freshwater fish, we monitored fish community changes, and compared fish fauna between dam reservoir and inflows. Additionally, movement characteristics and habitat boundaries of four species were identified by radio telemetry method. The study was conducted in the Gunwi Dam which was constructed in December 2010. Radio telemetry was applied to Pungtungia herzi, Zacco platypus (living lotic and lentic), Silurus asotus (lentic preferred species) and Zacco koreanus (lotic preferred species). The number of species was remarkably decreased (4 family, 10 species) comparing with before the dam construction (7 family, 15 species). Specifically, Coreoleuciscus splendidus, Niwaella multifasciata, Liobagrus mediadiposalis, Coreoperca herzi and Odontobutis platycephala that inhabit in the lotic environment were not collected in the study area. A total of 8 species were caught in both the dam reservoir and tributaries except 2 species (C. auratus and S. asotus). Sorenson's similarity between the reservoir and its tributaries was high (0.842). All of the radio tagged species stayed in the reservoir except S. asotus which moved to the tributary. These species mainly utilized the shallow littoral zone as a habitat. These results could be useful as a baseline data for efficient management of fishes in lakes.

• Journal of The Korean Association For Science Education
• /
• v.34 no.6
• /
• pp.549-558
• /
• 2014

Integrated concepts that are broad enough to embrace facts, principles, laws, and concepts of multiple disciplines could become the core of integrated education. Integrated concept-centered education enables effective and practical learning. In this study, the Delphi Method was implemented targeting experts in science (physics, life science, chemistry, and earth science) and humanities (history, geology, economics, ethics, and politics) to find out the integrated concept that can be used to design the concept-centered integrated education in the Republic of Korea. 124 experts participated in this survey. Delphi survey was conducted for three rounds. In the first round, an open questionnaire was given to experts to collect feasible integrated concepts in each major field. Then, in the second round experts were asked to select integrated concepts that could be used practically in the field of their major. In the third round, the integrated concept with selection frequency over medium value were given. They were asked to evaluate the applicability of integrated concepts by using the Likert-scale questionnaire. Through this process, content validity was analyzed. As a result, five integrated concepts (change, interaction, space-time, energy, and equilibrium) were selected for the inter-science integration. And thirteen integrated concepts (conflict, community, relationship, structure, power, diversity, culture, change, society, interaction, freedom, justice, and equality) were chosen for the inter-humanities integration. Finally, for the science-humanities integration, seven integrated concepts (structure, diversity, change, interaction, cycle, system, and environment) were determined.

• Journal of The Korean Association For Science Education
• /
• v.37 no.4
• /
• pp.539-552
• /
• 2017

The purpose of this study is to investigate the trends of model and modeling-related research in science education from 1989 to 2016 in Korea. Eighty-five (85) models and modeling-related journal articles were extracted from the KCI-listed journals and analyzed according to the criteria such as participants, research fields, research design, methods, data collection and elements of metamodeling knowledge. According to research participants, three out of four (3/4) were studied for students and the rest were for teachers. More than half of the studies for students were conducted with middle and high school students. The research fields of models and modeling-related researches in science education were comprised of earth science, chemistry, biology science, physics and science course. With regards to research design, the highest type is qualitative research and followed by hybrid research and quantitative research. According to research methods, the most numerous researches that were analyzed was the effectiveness of program, which was a developed model and modeling-related research. The analysis from the elements of the metamodeling knowledge showed most of model and modeling-related research utilized for the change of scientific concept or understanding.

• Polymer(Korea)
• /
• v.27 no.1
• /
• pp.9-16
• /
• 2003

Ipriflavone (IP) stimulates proliferation and differentiation of osteoblast and also enhances calcitonin secretion in the presence of estrogen. Poly(lactide-co-glycolide) (PLCA) due to its controllable biodegradability and relatively good biocompatibility is one of the most significant candidates for the study of drug controlled release system. In this study, IP-loaded PLGA microspheres (MSs) was prepared by using conventional O/W solvent evaporation method. The size of MSs was in the range of 5~200 $mu extrm{m}$. The morphology of MSs was characterized by SEM. And, in vitro release amounts of IP were analyzed by HPLC. The highest encapsulation efficiency were obtained by using gelatin and polyvinyl alcohol (PVA) as emulsifiers. The morphology, size distribution, and in vitro release pattern of MSs were changed by several preparation parameters such as molecular weights (8, 20, 33 and 90 kg/mol), polymer concentrations (2.5, 5, 10 and 20%), emulsifier types (PVA, gelatin and Tween 80), initial drug loading amount (5, 10, 20 and 30%) and stirring speed (250, 500 and 1000 rpm). The release of IP in vitro was more prolonged over 30 days, with close to zero-order pattern by controlling the preparation parameters. The physicochemical properties of IP-loaded PLGA MSs were investigated by XRD and DSC.