• The Korean Journal of Pesticide Science
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• v.3 no.1
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• pp.37-45
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• 1999

Dicamba (3,6-dichloro-o-anisic acid) granular formulations for controlled release (DGFCRs) were prepared with biodegradable polymers, corn starch and pregelatinized starch, to minimize harmful side effects, extend weed control performance, and control the releasing rate of the active ingredient. Physico-chemical properties and biological activity of DGFCRs were studied. Six different granules were formulated by applying two processes, granulation and extrusion. Formulation efficiencies of active ingredient (A.I.) in the granules prepared by granulating and extruding were $90.0{\sim}96.3%$. Incorporation ratios of A.I. in the granules prepared by granulating and extruding showed $89.5{\sim}94.5%$ and $46.7{\sim}82.0%$, respectively. The highest swellability was DG-2 formulation prepared with corn starch. Whereas, the lowest floatability in water was DG-2 formulation, while the highest one was DG-1 formulation prepared with pregelatinized starch, Miragel 463. The degradation rates of dicamba in the granules under the elevated temperature of $50^{\circ}C$ were less than 5% for DG-1 and DG-2 formulations even after 90 days, meanwhile, those of DE-1 formulations prepared with pregelatinized starch, Mirasperse, were more than 5%. The release rates of A.I. from the granules into water under a static condition were about 100% after 2 weeks. Weeding effects of the granules on broad leaf weeds tested in greenhouse were more than 90% after 30 days.

• Korean Journal of Food Science and Technology
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• v.32 no.1
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• pp.140-146
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• 2000

The physicochemical properties, such as retrogradation, fat acidity and viscosity, on the pine nut's gruel at various contents of pine nut (0, 1, 3 and 5%) during storage at 4, 25 and $40^{\circ}C$ were investigated. The degree of retrogradation was increased rapidly at the initial storage stage. The lowest value (about 10%) of the degree of retrogradation was observed in the gruel sample containing 3% of pine nut. Also, the rate constant of retrogradation was showed the lowest value (0.0422) in the gruel containing 3% of pine nut regardless of storage temperatures. The fat acidity was showed the lower value than 30 mg KOH in all samples. The viscosity increasing velocity(RVU/min) between holding strength and final viscosity was decreased as the pine nut's content was increased. However, it was not affected by the storage temperatures.

• Korean Journal of Microbiology
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• v.33 no.4
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• pp.267-273
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• 1997

Various physico-chemical and microbiological parameters of a composting system were compared with respect to their potential use for the monitoring and evaluation of composting processes for cattle manure. The temperature changed within a range of $30-65^{\circ}C$ during the whole composting process, and the period of active composting (>$40^{\circ}C$) persisted for 16 days. The concentrations of total carbon, total nitrogen, and organic matter decreased by 15% during active composting, but significant changes in C/N ratio were not observed. The decrease of temperature in the latter period of active composting caused a decrease of $NH_4^+-N$ and an increase of $NO_3^--N$ in the composting pile. When temperature exceeded $50^{\circ}C$, the population of thermophiles was higher than that of mesophiles by more than 1 or 2 orders of magnitude. Correlation analyses showed that amylase activity correlated positively with the population of mesophiles and reducing sugar content, but negatively with the population of thermophiles. Amylase activity was higher at the beginning of active composting, whereas cellulase, xylanase and ligninase activities which showed close relationship with each other, increased continually during active cornposting, suggesting the distinction of temporal niches between amylose-degrading and lignocellulose-degrading bacteria in the same habitat.

• Korean Journal of Ecology and Environment
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• v.56 no.3
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• pp.229-241
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• 2023

Microphysogobio rapidus is designated as endangered species class I by Ministry of Environment, and its distribution and population have been gradually declining, and it is now limited to the Nam River and some tributary streams of the Nakdong River Watershed. For the restoration of this highly endangered species, it is important to identify the causes of the decline and establish appropriate restoration plans. However, due to lack of basic data and ecological research, most steps are stagnant. Therefore, in this study, we identified the differences in the physical, biological, and sociological habitats between current and past distributed sites through field surveys and literature reviews. As a result of the field survey, there were differences in conductivity between the current and past distributed sites, and fish communities were also showed differences. The literature data also showed that the physico-chemical values of the past distributed sites were generally unfavorable, which generated negative consequences on biological factors. In particular, the effects of urbanization were found to be a major factor affecting the habitat of M. rapidus. Habitat stabilization is crucial for the recovery of this endangered species. However, in the past distributed sites, disturbances such as stream development and weir construction have altered streams physico-chemically and result in changes of M. rapidus. Therefore, a comprehensive plan that considers both stream connectivity and water quality is needed to manage and restore the habitat of M. rapidus.

• Polymer(Korea)
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• v.39 no.1
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• pp.114-121
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• 2015

Mutli-walled carbon nanotubes (MWCNTs) were surface-modified by a hydrofluoric acid solution to remove impurities and improve interfacial bonding and dispersion of nanotubes in an epoxy matrix. The crystallinity on the surface of treated MWCNTs was investigated by X-ray photoelectron spectroscopy and Raman spectroscopy. The mechanical properties were characterized by tensile test, and the enhancement of mechanical properties of the modified MWCNTs/epoxy composites was indicated by a 33% increase in tensile strength. The electromagnetic interference shielding effectiveness (EMI-SE) of modified MWCNTs/epoxy composites was improved with an increase in concentration of hydrofluoric solution, and EMI-SE showed the maximum increase with 25% HF. However, mechanical and EMI-SE properties didn't show further increase with over 50% HF concentration because the properties of MWCNTs were influenced by degradation of crystallinity and intrinsic properties of MWCNTs. The mechanical and electrical property enhancements of the polymer composites are attributed to the modification of MWCNTs which improve crystallinity of MWCNTs and dispersion in the epoxy resin.

• Korean Journal of Soil Science and Fertilizer
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• v.27 no.2
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• pp.111-116
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• 1994

These studies were carried out to investigate the possibility on the agricultural utilization of lake sediment collected in the Daecheong Lake. Several parameters to estimate the degree of maturity of compost by windrow system were tested during a 50 day periods, and the results were as follows : During the composting of Daecheong Lake sediment, C/N ratio decreased gradually from 18.9 at the beginning to 13.1 at the final, while CEC increased from 33.5me/100g to 62.5me/100g. The temperature of lake sediment pile was the highest as $52^{\circ}C$ at 15th day and then decreased slowly until $30^{\circ}C{\sim}40^{\circ}C$ after 50 days. The results may be suggested that Daecheong Lake sediment compost reaches an acceptable level of stability after about 50 days. In order to know the effect of the Lake sediment and its compost on the growth of tomato(Lycopersicum esculentum M.), pot experiments were performed. The appiication of lake sediment(AS) itself, sediment organic fertilizer(SOF), and NPK mixed with sediment organic fertilizer(NSF) was more effective for tomato plant height, fresh and dry weight, and chlorphyll content than those of control treatment. Also, the lake sediment compost improved the physico-chemical properties of soil such as pH, total carbon, total nitrogen, available phosphorous and CEC.

• Korean Journal of Environmental Agriculture
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• v.24 no.4
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• pp.319-325
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• 2005

Sediments of Mankyung and Dongjin river were examined on the physico-chemical properties and phosphorus fractionations. The content of total-P in sediment of Mankyung river ranged from 290.1 to 405.4 mg/kg (average = 363.4 mg/kg), while that in sediment of Dongjin river ranged from 304.1 to 431.7 mg/kg (average = 353.6 mg/kg). In both rivers, the total-P was highest in June to September. It is presumed that surficial sediment in arable land flowed into the rivers with rainfall-runoff. Phosphorus fractionations in Mankyung and Dongjin river were apatite-P 52.1% and 42.7%, residual-P 27.3% and 34.2%, nonapatite inorganic-P 18.1% and 22.5%, and adsorbed-P 0.6% and 0.6%, respectively. Adsorbed-P in sediment was the most scarcity fraction. It thus appears that adsorbed phosphorus was not effected in aquatic ecosystem. But nonapatite inorganic-P would be highly released under changes of redox condition and pH in aquatic ecosystem.

• Applied Biological Chemistry
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• v.22 no.1
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• pp.58-63
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• 1979

The solvent extracting of the tobacco has been carried out in order to find out any effects for the removal and/or reduction of nicotine from tobacco without affecting the tobacco flavor. We have now completed the physico-chemical characterization of the solvent untreated/treated tobaccos and 2) the contents of the tar and nicotine in the smoke. The results obtained ate like followings; 1. 3% alcohol extraction reduced the total nitrogen content for the Bright by 36.4%. However, it could not reduce the sugar content. 2. Nicotine content in tobacco leaves was inversely proportional to the dipping time Essentially same results were obtained in anacidic solution and even in a solution containing both alkali and acid. 3. Derivative thermogravimetric(DTG) curves indicated test extraction was effective by removing tobacco leaf components which could decompose or volatilize between the temperature of $150^{\circ}C\;and\;350^{\circ}C$. 4. 3% alcohol extracted leaf have the substantial improvements as following; (1) bulk filling power of 10% and 24% for Burley and Bright tobacco, respectively, (2) combustibility shortening of about 3 minute and 2 minute for Burley and Bright tobaccos, respectively, (3) reduction ratio(%) of nicotine was found to be shout 61.5% and 54.5% for Burley and Bright tobacco, respectively, (4) reduction ratio (%) of tar was obtained to he about 25% and 15% for Burley and Bright tobacco, respectively.

• The Korean Journal of Pesticide Science
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• v.2 no.1
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• pp.59-64
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• 1998

In order to elucidate the leaching behaviour of the herbicide bentazon in soil, soil columns(5cm ID ${\times}$ 34 cm L) were packed with three different soils up to 30 cm height, followed by the treatment of [$^{14}C$]bentazon, and rice plants(Oryza sativa L.) were grown for 9 weeks on these columns, with the columns without growing rice plants as the control for comparison. The amounts of $^{14}C$ activities percolated were about 92% of the originally applied $^{14}C$ irrespective of the physicochemical properties of the soils in the absence of rice plants, whereas $21{\sim}50%$ of the originally applied $^{14}C$ was percolated in the presence of rice plants, suggesting that the amounts of $^{14}C$ leached decreased remarkably in rice-cultivating soils. Bentazon leached faster in soil with higher pH and with lower organic matter content in the presence of growing rice plants. The amounts of $^{14}CO_{2}$ evolved from the soil columns were less than 0.2% of the originally applied $^{14}C$. Smaller amounts of $^{14}C$ were translocated into shoots via roots in soils with higher organic matter content. $^{14}C$ activities distributed into the aqueous phase of the leachate collected from the soil columns increased with leaching period and by rice cultivation, whereas the physico-chemical properties of soils did not exhibit any effect. The amounts of soil-bound residues increased remarkably by cultivating rice plants.

• Applied Chemistry for Engineering
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• v.30 no.5
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• pp.556-561
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• 2019

In this study, the physical and chemical analyses of petroleum residues (pyrolized fuel oil, PFO) were conducted and major components were selected to investigate their fire and explosion characteristics. Major component distribution areas of the PFO were identified via the GC-SIMDIS and MALDI-TOF analyses. In addition, the qualitative analysis of major component distribution areas was performed by GC-MS analysis. Major components of pyrolysis residue were selected based on the results of various analyses such as EA, SARA and TGA. As a result, benzene, toluene and xylene were selected as major components. Finally, the process hazard analysis software tool (PHAST) analysis was performed to investigate the range of maximum damage effect in case of fire and explosion. Toluene presented the highest risk due to the radiation effect of $227kW/m^2$ and 118 m in the case of jet fire. Xylene and benzene showed the maximum radiant heat values of 114 and $151kW/m^2$, respectively. It was also confirmed from the analysis of pasquill stability and wind speed that the radiant heat increased up to 55% according to wind speed in benzene, which was considered to be a main factor increasing the influence range.