• International Journal of Highway Engineering
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• v.6 no.3 s.21
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• pp.47-54
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• 2004

The performance of road-pavement system is closely related to the constituent materials and their susceptibility to mechanical as well as physicochemical stresses. However, the influence of physical and chemical effects on the road-pavement system due to pollution intrusion has not been investigated fully. To study this topic, thu.;, the interaction of a road-pavement system with pollution sources and environments are identified and discussed preliminarily in this paper. Pollution intrusion to road-pavement system occurs by three basic mechanisms; 1) direct intrusion into pavement surface, 2) intrusion from the Right of way, and 3) physical-chemical-biological alterations. Pollution intrusion potential is closely related to material type, particle size, and climatological and topographical features. Stability and performance of road-pavement system is also directly affected by pollution intrusion. Based on these features, thus, engineers working in related to the road design, construction, and maintenance should be seriously considered this topic.

• Korean Journal of Environmental Biology
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• v.18 no.3
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• pp.299-305
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• 2000

To determine the effects of underlayer vegetation on soil properties, the profiles, physical, and chemical properties of soil were investigated upon Fagus multinervis -Rumohra standishii, Fagus multinervis - typical, and Fagus multinervis -Sasa kurilensis subcommunities that was growing at Songinbong area of Ullungdo. There were little differences in soil profile properties among the three subcommunities. Also, there were little differences in physical and chemical properties of soil among the three subcommunities, except exchangeable Ca concentration in 0-10 cm soil depth. However, the soils of the study area in 0-10 cm soil depth comprised high organic matter and total N concentration as in an average value of 21.6% and 0.74%, respectively. Also, the soil showed very low bulk density and pH as in an average value of 0.43 g/㎤ and 4.4 in 0-10 cm soil depth, respectively. Due to the high soil organic matter and total N concentrations and the low bulk density and pH, the soil properties of Songinbong area are different from those of other forest in Korea.

• 한국해양학회지
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• v.11 no.1
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• pp.25-33
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• 1976

The physical factors and chemical contents were studied at 8 stations within Masan Bay, differing in depth and location with respect to inner and outer harbours. It is a relatively small bay with a long and narrow outlet. The water temperature and salinity at the inner bay was rather subject to change on weather condition of the neighbouring land than on the effects of the water mass of outer bay. The high nutrient contents in the bay were caused by the sewage and industrial activities. The outer harbour was less polluted than that of the inner bay; the high contents were significantly decreased from the entrance of the outer harbour. While the high disolved oxygen contents, over saturation in the surface strata may be the result of nearly all year round phytoplankton blooms, the lack of oxygen contents in the bottom strata were caused by the inadequate mixing of water mass and organic matters. The frequent red tide in the area may be the results of inflowing raw sewage, industrial activities of neighbouring land and inadequate mixing of water masses.

• Journal of the Korean institute of surface engineering
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• v.54 no.6
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• pp.340-347
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• 2021

Among various metal oxide semiconductors, ZnO has an excellent electrical, optical properties with a wide bandgap of 3.3 eV. It can be applied as a photocatalytic material due to its high absorption rate along with physical and chemical stability to UV light. In addition, it is important to control the morphology of ZnO because the size and shape of the ZnO make difference in physical properties. In this paper, we demonstrate synthesis of size-controlled ZnO tetrapods using an atmospheric pressure plasma system. A micro-sized Zn spherical powder was continuously introduced in the plume of the atmospheric plasma jet ignited with mixture of oxygen and nitrogen. The effect of plasma power and collection sites on ZnO nanostructure was investigated. After the plasma discharge for 10 min, the produced materials deposited inside the 60-cm-long quartz tube were obtained with respect to the distance from the plume. According to the SEM analysis, all the synthesized nanoparticles were found to be ZnO tetrapods ranging from 100 to 600-nm-diameter depending on both applied power and collection site. The photocatalytic efficiency was evaluated by color change of methylene blue solution using UV-Vis spectroscopy. The photocatalytic activity increased with the increase of (101) and (100) plane in ZnO tetrapods, which is caused by enhanced chemical effects of plasma process.

• Journal of Adhesion and Interface
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• v.16 no.3
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• pp.101-107
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• 2015

Epoxy resin toughening agents such as core/shell nanoparticles, CTBN epoxy, polyester polyols, and polyurethane have been widely used in order to compensate for the brittleness and improve the impact resistance of the epoxy resin. In this work, a few tougheners mentioned above were individually added into adhesive compositions to observe the effects of physical and mechanical properties. Both flexural strength and flexural modulus were measured with UTM while impact strength was analyzed with Izod impact tester. The obtained results showed that the addition of toughening agents afforded positive performance in terms of flexibility and impact resistance of the cured epoxy resin. Furthermore, DMA experiments suggested that the trends of storage modulus data of each epoxy resin composition coincided with the trends of flexural modulus data. FE-SEM images showed that toughening agents formed circled-shape particles when it was cured in epoxy resin composition at high temperature by phase separation. The existence of particles in the cured samples explains why epoxy resin with toughener has higher impact resistance.

• Journal of the Korean Chemical Society
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• v.56 no.6
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• pp.725-730
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• 2012

HEMA (2-hydroxyethyl methacrylate), EGDMA (ethylene glycol dimethacrylate; cross-linker), MMA (methyl methacrylate) and AA (acrylic acid) were copolymerized with ethyl gallate and propyl gallate as additives in the presence of AIBN (2,2'-azobisisobutyronitrile; initiator). The measurement of physical properties of the produced copolymers exhibited that refractive index, water content, visible transmittance, tensile strength, and contact angle were in the range of 1.433-1.435, 38.71-38.99%, 85.4-88.8%, 0.2468-0.2740 kgf and $49.77-36.29^{\circ}$, respectively. The transmittances of the copolymers were measured to be in the range of 49.0-7.4% and 71.0-43.4% for UV-B and UV-A, respectively, indicating that the copolymers have UV-blocking effect. The produced copolymers containing ethyl gallate and propyl gallate satisfied the basic physical properties required for the fabrication of hydrogel contact lenses. The copolymers showed an increase of wettability and UV-blocking effects while having no significant change in water content compared to the gallate-free copolymers.

• Journal of Ecology and Environment
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• v.38 no.4
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• pp.517-528
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• 2015

Litter decomposition is an important process in terrestrial ecosystem. However, studies on decomposition are rare, especially in evergreen broadleaf trees. We collected the leaf litter of five evergreen broadleaf trees (Daphniphyllum macropodum, Dendropanax morbifera, Castanopsis cuspidata var. thunbergii, Machilus thunbergii and Quercus acuta), and carried out a decomposition experiment using the litterbag method in Ju-do, Wando-gun, Korea for 731 days from December 25, 2011 to December 25, 2013. Among the five experimental tree species, C. cuspidata var. thunbergii distribution was limited in Jeju Island, and D. macropodum was distributed at the highest latitude at Mt. Baekyang (N 35°40′). About 2% of the initial litter mass of D. macropodum and D. morbifera remained, while 20.9% remained for C. cuspidata var. thunbergii, 30.4% for M. thunbergii, and 31.6% for Q. acuta. D. macropodum litter decayed four times faster (k = 2.02 yr^-1) than the litter of Q. acuta (k = 0.58 yr^-1). The decomposition of litter was positively influenced by thermal climate such as accumulated mean daily air temperature (year day index) and precipitation, as well as by physical characteristics such as thickness (R²=0.939, P = 0.007) and specific leaf area (SLA) (R² = 0.964, P = 0.003). The characteristics of chemical composition such as lignin (R² = 0.939, P = 0.007) and water-soluble materials (R² = 0.898, P = 0.014) showed significant correlations with litter decomposition. However, the nutrients in litter showed complicated species-specific trends. The litter of D. macropodum and D. morbifera had fast decomposition despite their low nitrogen concentration and high C/N ratio. This means that the litter decomposition was more strongly affected by physical characteristics than chemical composition and nutrient content. On the other hand, the litter of Q. acuta which had the slowest decay rate had a high amount of N and low C/N ratio. Thus, the decomposition of Q. acuta litter was more affected by the P content of the litter than the N content, although all litter had similar physical characteristics.

• Journal of Applied Biological Chemistry
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• v.49 no.3
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• pp.95-100
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• 2006

Brown rice with a giant embryo (GE) was observed on the quality parameters of the enlargement of embryo, nutritional components, and physical properties, in comparison to normal embryo brown rice (NE). Also, the effects of germination on the quality parameters were examined. GE embryo was approximately 2.68 times larger than of NE rice. Total free sugars were significantly higher in GE rice (71.96 vs. 41.17 mg/100 g), and germinated rice increased in fructose, but decreased in sucrose and maltose. No significant difference in mineral contents was found in GE and NE rice and their germinated rice, whereas a significant increment was observed on reducing sugars and gamma-amino butyric acid (GABA) contents in GE rice. The lower water absorption index (WAI) of GE rice resulted in relatively lower pasting viscosity, whereas the increased WSI in germinated rice might be attributable to the significant increment of soluble components in GE rice.

• Asian Journal of Turfgrass Science
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• v.23 no.2
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• pp.271-278
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• 2009

This study was conducted to investigate the effect of the mixture ratio of the inorganic soil amendments on the soil physicochemical properties. In this experiment, three kinds of soil amendments which had similar pH, EC and particle size, the A, B and C, were tested. The mixture ratio of soil amendment were 0%, 3%, 5%, 7% and 10% (V/V) incorporated with sand which met to the USGA(United State of Golf Association) particle standard. To analyze the effects of amendment on chemical soil properties, pH, EC(electrical conductivity) and CEC(cation exchangeable capacity) were measured. The porosity, bulk density and hydraulic conductivity also measured to analyze the changes of physical properties. In the chemical properties, pH was significantly related to the mixture ratios of amendments, A and C(P<0.05), CEC and EC also related to the ratios of C(P<0.01). When the results were applied to the USGA standard of the soil physical properties, the optimum mixture ratios of each amendment were 3% in A and B, and 7~10% in C. To analyze the corelation of mixture ratio versus to physical character, volume of porosity was significantly related to the ratio of B (P<0.05), and showed similar corelation in porosity and hydraulic conductivity with ratio of C(P<0.05). These results indicate that types and mixture ratio of inorganic soil amendments should affect on soil physio-chemical properties of root zone on USGA sand green.

• Proceedings of KOSOMES biannual meeting
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• 2006.11a
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• pp.291-297
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• 2006

Recently it is a tendency that the use of the heavy fuel oil is investigated even from the middle&small class vessel in order to reduce the operating cost of vessel caused by with rise of international gas price. In this study, analyzed the physical & chemical properties and examined the effect of refining treatment and a fuel oil additive for MF30 fuel oil which is a mixture fuel oil mixed M.G.O and the heavy oil MF380 use to be possible in the middle&small class vessel. As a results, the effects of two of pre-refinery treatment methods as centrifugal purifier and heating & homogenizing system(M.C.H) are some feeble, but the pour point and the flash point came to be low more or less. The effect of property improvement which is caused by with the fuel oil additive did not appear positively.