• Journal of Surface Science and Engineering
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• v.1 no.1
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• pp.5-13
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• 1967

Up to this date, numerous methods of analysis of electropling solutions are published. Some, however, need lots of works before reaching final results, or require high technique and special instruments, and also some are unaccurate due to unclearnes of end point. Like our undevelop countries, technicians of electroplating shops are most high school graduates or under, and have not much knowledge on chemistry. Furthermore, those technicians have to control their plating solutions by themselves without having enough analytical laboratory equipment . Therefore, in this paper the simplest, besides accurate method is investigated after comparing numerous methods published. Among the methods of copper determinations from acid and alkaline copper plating baths, EDTA titration method are chosen, due to these methods are the simpest and fastest for the evaluation of metal content, without requirng any special instrument. For acid copper solutions, chelate titrations were accurate enough. Since the end point of titration of chelate method is variable according to the kind of indicators and other metal's coexisitence as well as solution component, many difficulties were encountered from cyanide copper, on the contrary of acid copper bath. PAN , PV, and MX indicators were tried , but it is found that MX is the best. In chyanide solution ,due to cyanide is the masking reagent , elimination of this component is essential , and finally found that elimination CN-by precipitation with AgNO$_3$ solution was the simplest and the most accurate way among others. This method was very accurate for the new plating solutions even coexistence with organic brightners. However used solutions for long months running have to be predetermined the accurate copper value by thiosulfate method form time to time, before chelate titration by means of AgNO$_3$ precipitation. Always some constant deviations will be seen according to the solutions nature. Therefore those deviation values have to be compensated each time.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.4
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• pp.575-581
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• 2000

Quality characteristics of kochujang prepared with appleand persimmon were investigated during 14 weeks of fermentation. The water activity decreased slightly during fermentation and was higher in kochujang (I) prepared with apple than in kochujang (II) prepared with presimmon. The reducing sugar contents increased from 10.95% in kochujang (I) and 10.30% in kochujang (II) to 16.68, 19.14% after 10 weeks of fermentation, respectively. The free sugar contents in kochujang (I) were maltose 10.55, glucose 8.47 and fructose, 3.02% after 12 weeks of fermentation. The free sugar content in kochujang (II) were maltose 10.55, glucose 21.65, glucose 8.71 and fructose 2.98 after 6 weeks of fermentation. The major free sugar in kochujang (I) and (II) was maltose. The organic acids detected in kochujangs were citric, malic, lactic and oxalic acids. The contents of citric acid and malic acid were higher than other acids in both kochujangs. The contents of total free amino acids were 187.59~420.94 mg% in kochujang (I) and 154.67~316.93 mg% in kochujang (II). The contents of aspartic acid, proline and glutamic acid were high in kochujang (I) and (II).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.1
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• pp.71-83
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• 1996

Seasonal samples of demersal fish in Chonsu Bay were collected by an otter trawl from May 1991 to February 1992, and analyzed in terms of species composition, abundance and community structure. These data were compared with those obtained just after reclamation in 1986. The species composition of the demersal fish of the present study shows a similar seasonal trend to the previous one. However, the abundance in some species was changed. Gobiid fish such as Cryptocentrus filifer, Chaeturichthys stigmatias and Acanthogobius hasta were diminished, while Repomucenus lunatus, Leiognathus nuchalis and Sillago japonica were increased. This change in abundance of the fish seems to be related to sedimentation of fine particles and irregular discharge of freshwater with high organic content from the reservoir to the bay.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.spc1
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• pp.214-222
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• 2006

Dominant species of macrobenthos were analyzed based on differentiation of three distinct methods: the density based method, the biomass based method and LeBris method, by considering the frequency of occurrence using quantitative data collected over 5 years (1993-1998) at 21 stations in Chonsu Bay. Sedimentary environments as well as species composition and diversity showed the spatial and temporal distribution patterns. The ranks of dominant species as determined by the density based method were more similar to the results by the LeBris method than to those from the biomass based method. Considering the temporal variation, LeBris method were more efficient than any other methods for the determination of dominant species in Chonsu Bay. Lumbrineris longifolia, Theora fragilis, and Moerella jedoensis were recognized by all three methods. A one-way analysis of variance indicated spatial distributions patterns among most of the dominant species. These species showed positive correlations to sedimentary parameters such as mean grain size. However, T. fragilis and Paraprinospio pinnata showed the temporal patterns in their distribution, and were also correlated to the benthic environment, organic content and dissolved oxygen. Some dominant species, e.g., T. fragilis, S. scutata, G. gurjanovae proved to be useful benthic indicators based on the environmental variations determinated by long-term benthic ecological monitoring in Chonsu Bay.

• Journal of Microbiology and Biotechnology
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• v.20 no.11
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• pp.1491-1499
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• 2010

Rhizosphere microorganisms possessing phytase activity are considered important for rendering phytate-phosphorus (P) available to plants. In the present study, the Citrobacter braakii phytase gene (appA) was overexpressed in rhizobacteria possessing plant growth promoting (PGP) traits, for increasing their potential as bioinoculants. AppA was cloned under the lac promoter in the broadhost-range expression vector pBBR1MCS-2. Transformation of the recombinant construct pCBappA resulted in high constitutive phytase activity in all of the eight rhizobacterial strains belonging to genera Pantoea, Citrobacter, Enterobacter, Pseudomonas (two strains), Rhizobium (two strains), and Ensifer that were studied. Transgenic rhizobacterial strains were found to display varying levels of phytase activity, ranging from 10-folds to 538-folds higher than the corresponding control strains. The transgenic derivative of Pseudomonas fluorescens CHA0, a well-characterized plant growth promoting rhizobacterium, showed the highest expression of phytase (~8 U/mg) activity in crude extracts. Although all transformants showed high phytase activity, rhizobacteria having the ability to secrete organic acid showed significantly higher release of P from Ca-phytate in buffered minimal media. AppA overexpressing rhizobacteria showed increased P content, and dry weight (shoot) or shoot/ root ratio of mung bean (Vigna radiata) plants, to different extents, when grown in semisolid agar (SSA) medium containing Na-phytate or Ca-phytate as the P sources. This is the first report of the overexpression of phytase in rhizobacterial strains and its exploitation for plant growth enhancement.

• Environmental Engineering Research
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• v.11 no.1
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• pp.14-27
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• 2006

The proper management of discarded electronic devices (often called electronic-waste) is an emerging issue for solid waste professionals throughout the world because of the large growth of the waste stream, and the content of toxic metals in them, most notably heavy metals such as lead. Notebook computers are becoming one of the major components of discarded computer devices and will continue to increase in the waste stream in the future. While the computers hold great promise for recycling, a substantial amount of this waste is often disposed in municipal solid waste (MSW) landfills. The toxicity characteristic leaching procedure (TCLP) is commonly used to simulate worse case leaching conditions where a potentially hazardous waste is assumed to be disposed along with municipal solid waste in a landfill with actively decomposing materials overlying an aquifer. The objective of this study was to examine leaching potential of lead from discarded notebook computers using the scale-up TCLP, other standard leaching tests such as California waste extraction test (Cal WET), and the synthetic precipitation leaching procedure (SPLP) and actual landfill leachates as leaching solution. The scale-up TCLP is a modified TCLP (where the device was disassembled and leached in or near entirety) to meet the intent of the TCLP. The results showed that the scale-up TCLP resulted in relatively high lead found in the leachate with an average of 23.3 mg/L. The average level was less than those by the standard TCLP and WET (37.0 mg/L and 86.0 mg/L, respectively), but much greater than those by the SPLP and the extractions with the landfill leachates (0.55 mg/L and 1.47 mg/L, respectively). The pH of the leaching solution and the ability of the organic acids in the TCLP and WET to complex with the lead were identified as major factors that controlled the amount of lead leached from notebook computers. Based on the results obtained by a number of leaching tests in this study, notebook computers may present a potential leaching risk to the environment and human health upon land disposal. However, further investigation is still needed to assess the true risk posed by the land disposal of discarded notebook computers.

• Journal of Environmental Impact Assessment
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• v.7 no.2
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• pp.37-51
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• 1998

This study was carried out to lead the scientific management of the urban forest by estimating the forest environment. Forest environmental information was constructed using IDRISI system based on survey data, soil, plant, and digital elevation data. Forest environmental information was consisted of soil depth, soil organic content, soil hardness and parent rock as a soil environmental factor, and forest community, tree age, crown density as a plant environmental factor. Plant activity and topographic environment also were analyzed by using remote sensing data and digital elevation data. Environmental function of urban forest was estimated based on results of soil conservation and forest productivity. 70% of urban forest is located in elevation of lower than 200m and 55% of forest area have the slope of lower than 15 degree. Analyzed soil conservation status and forest productivity were almost the same as the soil chemical properties of collected soil sample and the vegetation index estimated using remote sensing data, respectively. Thus, the constructed forest environmental information could be useful to give some ideas for management of urban forest ecosystem and establishment of environmental conservation planning, including forests, in Taejon. The best forest environmental function was appeared at the natural ecology preservation zone. Current natural parks and urban parks were appeared to establish the environmental conservation plan for further development. The worst forest environmental function was appeared at the forest near to the industrial area and an overall and systematic plan was required for the soil management and high forest productivity because these forest was developing a severe soil acidification and having a low forest productivity.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.6 no.5
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• pp.48-58
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• 2003

This study was carried out to select proper species for early stage replantation in granite forest road cut-slope. From one to thirteen year elapsed forest roads in five regional areas of Chungcheong-do and Kyungsangbuk-do, sample plots were selected, and their vegetations and environmental factors were investigated. Soil organic matter, total nitrogen, soil moisture content, and bulk density in the granite weathering soils were below 0.5%, 0.02%, 10%, and above 1.2g/$cm^3$, respectively. The environmental factors affecting distribution of species in the granite forest road were the elapsed year, elevation, cut-slope aspect, and cut-slope. Sowing plants of Dactylis glomerata, Lolium perenne, and Eragrostis curvula were found in the early stage of forest road-cut. Annual herbs of Youngia denticulata, Erigeron annuus, etc. were found in the 2-3 years elasped forest road-cut. Perennial herbs of Artemisia princeps var. orientalis, Miscanthus sinensis, etc., parachute woody plants of Weigela subsessilis, Pinus densiflora, etc., and gravitative trees of Prunus sargentii, Lindera obtusiloba, Quercus sp., etc. were found in the forest road cut-slope after 3 years of road-cut. Leguma of Lespedeza cureata, Amorpha fruticosa, Lespedeza bicolor, Pueraria thunbergiana, Albizzia julibrissin, etc., herbs of Artemisia keiskeana, Artemisia princeps var. orientalis, Miscanthus sinensis, etc., and woody plants of Rubus crataegifolius, Weigela subsessilis, Zanthoxylum schinifolium, Pinus densiflora, etc. were considered as proper species for replantation in granite forest road cut-slope.

• 한국해양학회지
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• v.30 no.4
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• pp.250-261
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• 1995

This study was carried out to investigate the distribution of the benthic polychaetous community in Kamak Bay, in summer of 1993. Polychaetes, the dominant faunal group comprising 74.5% of the total number of fauna, consisted of a total of 84 species with a mean density of 112 indiv.m/SUP -2/. The number of species and density were higher in the mouth area of the bay than in the rest of the bay. The most dominant Polychaete was Tharyx sp.(31.9%), followed by Lumbrineris longifolia (27.5%), Chone sp.(4.5%) and Glycera chirori (4.2%). The correspondence analysis revealed that the study area could be divided into four regions. Northeastern channel and southern mouth region of the bay, named Tharyx-Chone assemblage, sustained higher polychaetous density and species number due to the active water exchange with the outer off-sea, whereas northwestern region of the bay had the poorest polychaetous assemblage in the species number and faunal density owing to the blocking water exchange, high organic enrichment in sediment, and low dissolved oxygen content of bottom water. The central region, named Praxillella-Terebellides assemblage and Gly-cera assemblage, was the transition zone between another two region in species composition.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.26 no.2
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• pp.170-177
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• 2016

Objectives: This study was conducted to evaluate the total heavy metals contents and chemical forms in the animal manure compost. Materials and methods: A total of 109 compost samples were collected throughout the country and classified into three groups in accordance with the raw materials; pig manure, poultry manure and mixed(pig+poultry+cattle) manure. The compost samples were analyzed for total metal content and sequential chemical extraction to estimate the quantities of metals. Results: Concentrations of Zn and Cu in several compost samples were higher than the maximum acceptable limits by the Korea Compost Quality Standards. Concentrations of Zn, Cu, and Cd in compost samples were 257~5,102, 68~1,243, and 0.02~2.54 mg/kg respectively, while Cr, Ni, As, and Pb were < 20 mg/kg. The concentrations of heavy metals in pig manure compost were higher than those of both the poultry and the mixed manure compost. The predominant forms for extracted metals were Cr, Ni, Zn, As, and Pb, residual; Cu, organic; and Cd, carbonate. Conclusions: Results indicate that the Zn and Cu contents in compost were higher than other heavy metals and the heavy metal contents were greater in pig manure compost followed by mixed and poultry manure compost. To prevent the accumulation of heavy metals in soil where animal manure compost is applied, strategy for reducing heavy metal concentrations in animal manure and compost must be considered.