• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.2
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• pp.296-301
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• 1998

The physical and chemical characteristics were examined in the southern sea of Korea including the Cheju Strait, and the entrance of the Korea Strait in the period of May 30 to June 8, 1995. The results are as follows. Firstly, the variation ranges of the temperature and salinity at the Cheju Stratit during 24 hours observation were larger in the surface layer than that in the deep layers. Secondly, daily variations of nutrients show that total inorganic nitrogen, phosphate phosphorous, and silicate silicon concentration are higher at night than at day. Thirdly, water temperature and salinity distributions show highest values at the entrance of Korea Strait, which is thought to be influenced directly by Tsushima Warm Current, while they show the lowest values in Cheju Strait. This means that the surface waters in Korea Strait are greatly influenced from the entrance of Korea Strait and bottom waters is greatly influenced from Cheju Strait. Fourthly, nutrients distribution shows highest values in Korea Strait but dissolved oxygen shows lowest values in the area. These seem to be caused by the oxygen consumption used in the inorganization of nutrients to decompose organisms and the liquidation of nutrients.

• Journal of the Korean Institute of Landscape Architecture
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• v.33 no.5 s.112
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• pp.69-82
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• 2005

These studies were carried out (1) to investigate the growth characteristics of Sedum album L. in the field, (2) to propose a suitable shallow peen roof system for this plant, and (3) to evaluate plant growth in the proposed system over the long term. The growth characteristics, such as morphological properties, growth habit, shade tolerance, and flowering, were surveyed. In experimental shallow green-roof systems, the effects of drainage type, substrate type, and soil depth on plant growth were investigated. Then drought tolerance was investigated. After planting Sedum album L. in the proposed system survival rate, cover, and resistance to insects, heal and cold were evaluated for about 2 years. The results of these studies are summarized below. 1. In the field, the aboveground part of Sedum album L. did not die back during the winter. Plant height was 4$\sim$7 cm. Roots were distributed to a depth of 5$\sim$7 cm. Sedum album L. is a compact ground-cover plant that spreads vigorously. Shading condition of less than $30\%$ of full sunlight didn't cause any trouble, but shading conditions above $87\%$ made the shape of the shoots and leaves abnormal. The plant bloomed from June to August and had a rather large compound umbel of white, star-shaped flowers. 2. Two systems, a drainage-blend-10 cm soil depth and a reservoir$\cdot$drainage-blend-15 cm soil depth, performed best in terms of cover, fresh weight, and dry weight. The first has an advantage for green roofs because it is lighter than the latter. 3. In drainage-blend-10 m soil depth and modified reservoir · drainage-blend-10 cm soil depth system no plants died for about 4 months after stopping the irrigation. The visual quality of the latter system was above 5 for 4 months and that of the former was under 5 after 2 months. In the field, however, the drought tolerance of Sedum album L. grown in the former would be enough to withstand the dry season. Considering the urban ecosystem and the importance of healthy growth the modified reservoir $\cdot$ drainage-blend-10 cm soil depth system was finally recommended. This system was composed of a 4 cm thick drainage layer and drain outlets placed at a height of 2.5 cm. 4. In the proposed system, the survival rate was $100\%$, and there was no injury induced by insects and heat. The leaf density decreased a little in winter. Cover increased throughout the year. Sedum album L. was planted with a cover of 72$cm^{2}$ on 3 April 2003; on 16 June 2003 and 15 June 2004, cover was $132.66\pm$5.87 $cm^{2}$(1.8 times) and $886.98\pm$63.51 $cm^{2}$(12.3 times), respectively.

• Journal of Korea Multimedia Society
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• v.14 no.11
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• pp.1438-1449
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• 2011

UWSNs(Underwater Wireless Sensor Networks) need effective modeling fitted to the customized type of application and its covering area. In particular it requires an energy efficient data aggregation method for such customized application. In this paper, we envisage the application oriented model for monitoring the pollution or intrusion detection over a given underwater area. The suggested model is based on the honeycomb array of hexagonal prisms. In this model, the purpose of data aggregation is that the head node of each layer(cluster) receives just one event data arrived firstly and transfer this and its position data to the base station effectively in the manner of energy efficiency and simplicity without duplication. Here if we apply the existent data aggregation methods to this kind of application, the result is far from energy efficiency due to the complexity of the data aggregation process based on the shortest path or multicast tree. In this paper we propose three energy efficient and simple data aggregation methods in the domain of cluster and three in the domain of inter-cluster respectively. Based on the comparative performance analysis of the possible combination pairs in the two domains, we derive the best energy efficient data aggregation method for the suggested application.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.24-25
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• 2006

SmBCO coated conductors were successfully fabricated using EDDC (Evaporation using Drum in Dual Chambers) deposition system that is a bath type co-evaporation system for fabrication of superconducting tape and divided into two chambers named evaporation chamber and reaction chamber. To obtain long and high quality superconducting coated conductor, it is very important to secure the uniformity of all the deposition parameters m the deposition system such as deposition temperature, oxygen partial pressure, compositional ratios and so on. Therefore, we investigated the distribution of the parameters along the axis of the drum m EDDC on which tapes were wound helically. When the temperature on the middle point of deposition zone was $700^{\circ}C$, that on the edge of deposition zone was $675^{\circ}C$. When the thickness of SmBCO layer on the middle point of deposition zone was 1063 nm, that on the edge of deposition zone was 899 nm. The partial pressure of oxygen was 5 mTorr in the reaction chamber while that was $7{\times}10^{-5}$Torr in the evaporation chamber. The composition ratio of Sm:Ba:Cu, that was measured by EDX, was very uniform along the axis of the drum. Under these deposition conditions, critical current distribution along the drum axis was 175 A/cm, 190A/cm, 217.5 A/cm, 182.5 A/cm, 175 A/cm with the interval of 9 cm between samples. It means that the EDDC system has the potential of fabricating (100m, 200A) class coated conductor.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.186-195
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• 2016

We investigated phytoplankton and vertical inorganic nutrients at two stations around water of Ulleungdo and Dokdo in the East Sea, Korea. Nutrient addition experiments (+N, +P, +NP and +Fe) were also conducted to determine the growth response and nutrient consumption of the phytoplankton assemblage using the surface water of St. UD3 and St.50. In the field, although inorganic nutrients were low in the euphotic layer, these nutrients were increased at depths below 100 m. The total phytoplankton abundances in St. UD3 and St.50 were $4.9{\times}10^5cells\;L^{-1}$ and $1.9{\times}10^5cells\;L^{-1}$, respectively. The dominant species at St. UD3 was observed to be Raphidophyta Heterosigma akashiwo, Cryptophyta Crytomonas spp., and diatom Leptocylindrus danicus, while L. danicus and H. akashiwo including small diatom species Chaetoceros socialis were dominant at St. 50. In the nutrient addition experiments, phytoplankton growth (in vivo flourescence) in the +N and +NP treatment was 2-3 times higher than that in the +P treatment, indicating that the natural phytoplankton can respond to pulsed nutrient loading events. In addition, in vivo fluorescence in +Fe treatment was not statistically (p>0.05) different from that of the non-Fe treatments, indicating that the phytoplankton growth response in +Fe treatment was not significant. Dominant H akashiwo and L. danicus in the field showed a rapid response in nutrient additional bio-algal assay, particularly L. danicus in the +Fe treatments.

• International Journal of Highway Engineering
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• v.13 no.4
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• pp.117-122
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• 2011

Asphalt concrete pavement can be widely seen on urban streets, highways, parking lots, and bike trails. Asphalt concrete pavement is relatively temperature sensitive materials due to the viscoelastic behavior, which can be defined as flexible performance in summer and rigid performance in winter. In terms of maintenance, it can be fixed quite easily if damaged. In addition, asphalt concrete pavement is generally found to be black and grey in color. However, several colors can be adopted to change the appearance of plain old boring, black and grey. Generally, there are two types of color systems in hot mix asphalt concrete materials. One system uses colored cementitious material that is applied to pavement surface through coating the surface of the asphalt pavement. The major disadvantage to this system requires a careful skill set to be used on the construction site in order to prevent taking off the cementitious material. The other coloring system colors the asphalt hot mixtures through using color additives. The main advantage to this system is that the asphalt pavement layer is colored using the same techniques that are already used in paving. The disadvantage is that the colors are limited to mainly reds and browns. In this study, a suggested color additive was evaluated, based on rutting, moisture sensitivity, and fatigue cracking performance.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.8.1-8.1
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• 2011

Nanocrystalline titanium dioxide ($TiO_2$) materials have been widely used as an electron collector in DSSC. This is required to have an extremely high porosity and surface area such that the dye can be sufficiently adsorbed and be electronically interconnected, resulting in the generation of a high photocurrent within cells. In particular, their geometrical structures and crystalline phase have been extensively investigated as important issues in improving its photovoltaic efficiency. In this study, we present a new strategy to fabricate a photoelectrode having a periodic structured $TiO_2$ film templated from 1D or 3D polystyrene (PS) microspheres array. Monodisperse PS spheres of various radiuses were used for colloidal array on FTO glasses and two types of photoelectrode structures with different $TiO_2$ materials were investigated respectively. One is the igloo-shaped electrode prepared by $TiO_2$ deposition by RF-sputtering onto 2D microsphere-templated substrates. At the interface between the film and substrate, there are voids formed by the decomposition of PS microspheres during the calcination step. These holes might be expected to play the predominant roles as scattering spherical voids to promote a light harvesting effect, a spacious structure for electrolytes with higher viscosity and effective paths for electron transfer. Additionally the nanocrystalline $TiO_2$ phase prepared by the RF-sputtering method was previously reported to improve the electron drift mobility within $TiO_2$ electrodes. This yields solar cells with a cell efficiency of 2.45% or more at AM 1.5 illumination, which is a very remarkable result, considering its $TiO_2$ electrode thickness (<2 ${\mu}m$). This study can be expanded to obtain higher cell efficiency by higher dye loading through the increase of surface area or multi-layered stacking. The other is the inverse opal photonic crystal electrode prepared by titania particles infusion within 3D colloidal arrays. To obtain the enlargement of ordered area and high quality of crystallinity, the synthesis of titania particles coated with a organic thin layer were applied instead of sol-gel process using the $TiO_2$ precursors. They were dispersed so well in most solvents without aggregates and infused successfully within colloidal array structures. This ordered mesoporous structure provides the large surface area leading to the enough adsorption of dye molecules and have an light harvesting effect due to the photonic band gap properties (back-and-forth reflection effects within structures). A major advantage of this colloidal array template method is that the pore size and its distribution within $TiO_2$ photoelectrodes are determined by those of latex beads, which can be controlled easily. These materials may have promising potentials for future applications of membrane, sensor and so on as well as solar cells.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.570-576
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• 2002

Application of the aged Inconel 718 in hydrogen environment is seriously restraint by its high hydrogen embrittlement (HE) sensitivity. m previous researches, we have suggested the possibility and applicability of the laser surface annealing (LSA) process in improving the HE resistance of this alloy. Sequentially, a study on the effects of the precipitates in the Inconel 718 on its HE sensitivity was conducted in this research. Firstly, flat bar specimens were heat-treated to obtain various kinds of precipitation microstructures concerning the ${\gamma}$" phase and the 6 phase. Hydrogen was charged into the specimen by a cathodic charging process. The loss in reduction of area (RA) caused by hydrogen charging was used to assess the HE sensitivity. The HE sensitivity of the alloy was lowered with decreasing the volume fraction of ${\gamma}$". Moreover, it was possible to increase the HE resistance of the aged alloy by dissolving the $\delta$ phase, keeping the strength at the same level as that of the common aged alloy. Thus, we concluded that both the $\delta$ phase and the ${\gamma}$" phase affected the HE sensitivity of Inconel 718. Next, two kinds of notch tensile specimens were fabricated, one kind having $\delta$ phase and the other having no $\delta$ phase. All these specimens were aged via the same aging heat treatment process. The LSA process annealed a thin layer of the notch bottom of each specimen. One specimen of each kind was charged with hydrogen by the cathodic hydrogen charging process. Loss in the notch tensile strength (NTS) caused by hydrogen was used to evaluate the HE sensitivity. It was found that while the HE sensitivity of conventionally aged Inconel 718 was decreased by the LSA process, the HE sensitivity of the $\delta$-free aged Inconel 718 could further be decreased. Therefore, for applications in hydrogen environments, it is possible to fabricate alloys with both good HE resistance and high strength by controlling the precipitation conditions, and to improve HE resistance further via applying the LSA process.

• Korean Journal of Veterinary Research
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• v.16 no.1
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• pp.11-25
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• 1976

Studies on pathogenicities and developmental stages of Nosema apis (Zander, 1909) were carried out through artificial infection to Nosema free honey bees with various levels of spores isolated from local honey bee colony. The results obtained were summarized as follows: 1. The clinical symptoms were observed as dysentery, enteritis of mid-gut (enlargement and decoloration), crawling posture and shortening of the longevity of worker bees in the rearing honey bee colony inoculated with the spores. 2. Number of spores harvested from laboratory rearing honey bees were progresively increased to 4 weeks after inoculation. The regression equations and coefficients of correlations to various spore levels were as follows in each treatment colony. Colony 1. ($$1,000{\times}10^4spores/ml$$) $$y_{c1}=471{\times}10^{4}x+454{\times}10^4(r=0.65^*$$) Colony 2. ($$500{\times}10^4spores/ml$$) $$y_{c2}=340{\times}10^{4}x+207.8{\times}10^4(r=0.99^{**}$$) Colony 3. ($$100{\times}10^4spores/ml$$) $$y_{c3}=150{\times}10^{4}x+84.2{\times}10^4(r=0.99^{**}$$) Colony 4. ($$10{\times}10^4spores/ml$$) $$y_{c4}=13.8{\times}10^{4}x+13{\times}10^4(r=0.98^{**}$$) 3. Average longevity of worker bees artificially infected with Nosema apis was shortened as 21.7~43.8% compare to the control. (p<.05, p<.01) 4. The spores which were isolated from honey bee colony infected with Nosema disease were ovoid or spherical form, and measured, as a rule, from $4.7{\mu}m$ to $6.1{\mu}m$ (mean $5.3{\mu}m$) in length and from $2.4{\mu}m$ to $3.2{\mu}m$ (mean $2.9{\mu}m$) in width. 5. In the mid-gut of honey bees, the spore was progresively germinated and became trophozoite stage. The trophozoites were grown to meronts and their binary fission were begun. The divided two sporoblasts were developed to the spores which had elastic membrane. The new spores were shed in excreta of honey bees 10~15 day after inoculation at $25{\pm}2$ centigrade. 6. The ultrastructure of spore membrane consisted of three layers, such as, outer, middle and inner layer. The sporoplasm consisting lamellar structure occupied only anterior part of the spore and was often extended to posterior direction where definite vacuoles and a polar filament was able to detect.

• Journal of the Korean Wood Science and Technology
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• v.41 no.1
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• pp.42-50
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• 2013

Since 1990's, a plywood for flooring base has gotten customers' demand. Costs of raw material and production increased because of changed environment of industry. Tropical timber such as Red Meranti (Shorea acuminate) used for raw material of the floor has been depleting beside countries in South Eastern Asia changed species of afforestation. As a result, it gets hard to secure good quality of raw material for plywood. Moreover plywood price is increased suddenly after earthquake in Japan. Eucalyptus (Eucalyptus globulus) in china has been using for raw material as a countermeasure of changed environment of industry. In this study, possibility of using flooring consisted of Eucalyptus veneer as crossband layers was checked by deflection experiments. Flooring consisted of Red Meranti was used for comparison. Two factors which impact on deflection are a type of density gradient and density difference between Long-grain veneer and Short-grain veneer. Red Meranti samples are M type of density gradient on the other hand Eucalyptus samples are W type of density gradient. The more samples have high density difference, the more deformation was checked. A sample which has big density difference between core and cross bands layer warp more also deform. Flooring was deformed smaller than plywood and samples which have big density difference was deformed more.