• Korean Chemical Engineering Research
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• v.56 no.3
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• pp.320-326
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• 2018

In this study, Graphite/Silicon/Carbon (G/Si/C) composites were synthesized to improve the electrochemical properties of Graphite as an anode material of lithium ion battery. The prepared G/Si/C composites were analyzed by XRD, TGA and SEM. Also the electrochemical performances of G/Si/C composites as the anode were performed by constant current charge/discharge, rate performance, cyclic voltammetry and impedance tests in the electrolyte of $LiPF_6$ dissolved inorganic solvents (EC:DMC:EMC=1:1:1 vol%). Lithium ion battery using G/Si/C electrode showed better characteristics than graphite electrode. It was confirmed that as the silicon content increased, the capacity increased but the capacity retention ratio decreased. Also, it was shown that both the capacity and the rate performances were improved when using the Silicon (${\leq}25{\mu}m$). It is found that in the case of 10 wt% of Silicon (${\leq}25{\mu}m$), G/Si/C composites have the initial discharge capacity of 495 mAh/g, the capacity retention ratio of 89% and the retention rate capability of 80% in 2 C/0.1 C.

• Biomedical Science Letters
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• v.16 no.4
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• pp.213-220
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• 2010

Although an adequete intake of calcium (Ca) is recommended for the treatment and prevention of osteoporosis, the intake of Ca should be restricted because of its low rate of intestinal absorption. The purpose of this experiment was to identity the effect of the combined administration of Aquamin F (AQF) (a calcium agent) and lactic acid bacteria (LAB) on osteoporosis. Thirty ovariectomized (OVX) rats and six control rats were assigned to the following six groups, with six animals per group: sham Ca-deficient diet (Ca-D), OVX, LAB, AQF, and LAB-AQF. During the experiment, the body weight was measured; and after the experiment was completed, the serum biochemical analysis, the alkaline phosphatase, calcium, and inorganic phosphorus leves were measured. The tissue of the femur was stained and then scanned via CT. The body weight of the OVX group increased more significantly than that of the control group. The results of the bone mineral content (BMC), Bone mineral density (BMD), serum biochemical analysis and histological test on the femur epiphysis showed no difference between the OVX group and the LAB group, whereas the results of the AQF group were more significant than those of the OVX group. In particular, the LAB+AQF group showed more significant increases in the aforementioned results than the AQF group. This experiment showed that the combined administration of AQF and LAB in ovariectomized rats more significantly increased bone density than did a single administration of either AQF or LAB.

• Korean Journal of Plant Resources
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• v.19 no.2
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• pp.265-272
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• 2006

This study was conducted to investigate the efficient propagation method of Cyrtomium caryoptideum var. coreanum by sporophyte culture. The influence of origin of explant sources (rhizome, blade, or stipe) and homogenization of culture materials on shoot regeneration were investigated. As a result, only rhizome explant exhibited the organogenic capacity and the shoot regeneration was promoted by homogenization of culture material. Vigorous and excellent growth of multiple shoots was induced on the half-strength of inorganic salts containing MS medium. It was appeared that optimum nitrogen content of shoot regeneration was half-strength of nitrogen containing MS medium (30mM) and optimum sucrose concentration was 1%. Addition of $NaH_2PO_4$ to culture medium generally enhanced shoot multiplication and promoted growth of the regenerants. The organogenic capacity of homogenized rhizomes was especially promoted on medium supplemented with $5{\mu}M$ kinetin plus $5{\mu}M$ IBA. The incorporation of $0.1\sim0.2%$ activated charcoal on medium supplemented with growth regulators prevented the formation of multiple bud primordia - nodule-like bud clusters and improved the normal morphogenesis of sporophytes.

• ALGAE
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• v.23 no.3
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• pp.241-250
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• 2008

Since seagrasses in the coastal and estuarine ecosystems achieve high levels of production, they require high inorganic carbon and nutrient incorporation. Thus, seagrasses may play a significant role in carbon and nutrient cycling in the coastal and estuarine ecosystems. To examine growth dynamics of Zostera marina L. environmental factors such as underwater irradiance, water temperature, and salinity, and biological parameters such as shoot density, biomass, shoot morphology, and leaf productivity were measured in two bay systems (Jindong Bay and Gamak Bay) on the southern coast of Korea. While underwater irradiance did not show distinct seasonal trend, water temperature at both sites exhibited clear seasonal trend throughout the experimental period. Shoot density increased dramatically during winter due to the increased seedlings through germination of seeds in Jindong Bay and due to the increased lateral shoots in Gamak Bay. Eelgrass biomass increased during winter and decreased during summer. Maximum biomass in Jindong Bay and Gamak Bay was 250.2 and 232.3 g dry weight m–a2, respectively. Carbon incorporation into the eelgrass leaf tissues was estimated from productivity and leaf tissues carbon content. The calculated annual carbon incorporations at the Jindong Bay and Gamak Bay sites were 163 and 295 g C m–`2 y–`1, respectively. This high carbon incorporation into seagrass tissues suggests that seagrass habitats play an important role as a carbon absorber in the coastal and estuarine ecosystems.

• KSBB Journal
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• v.31 no.3
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• pp.158-164
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• 2016

Plant growth promoting (PGP) hormones, which are produced in a small quantity by bacteria, affect in plant growth and development. PGPs play an important role on the crop productivity in agricultural field. In this study, a photosynthetic bacterial strain producing the PGP was isolated from paddy soil. Bacterial isolate was gram negative, rod-shaped and motility positive. From the 16s rRNA gene sequence analysis, the isolate was identified as Rhodobacter capsulatus PS-2. The mass cultivation of R. capsulatus PS-2 was optimized by considering of the carbon, nitrogen and inorganic salt sources. Optimal medium composition was determined as Na-succinate 4.5 g, yeast extract 5 g, $K_2HPO_4$ 1 g, $MgSO_4$ 5 g, per liter. From the result of 500 L fermentation for 2 days using the optimal medium, the viable cells were $8.7{\times}10^9cfu/mL$. R. capsulatus PS-2 strain produced the carotenoid and indole-3-acetic acid (IAA). The carotenoid extraction and quantitative analysis were performed by HCl-assisting method. Total carotenoid contents from R. capsulatus PS-2 culture broth were measured as $7.02{\pm}0.04$ and $6.93{\pm}0.05mg/L$ under photoheterotrophic and chemoheterotrophic conditions, respectively. To measure the productivity of IAA, colorimetric method was employed using Salkowski reagent at optical density 535 nm. The results showed that the highest content of IAA was $197.44{\pm}5.92mg/L$ in the optimal medium supplemented with 0.3% tryptophan.

• Composites Research
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• v.33 no.1
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• pp.7-12
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• 2020

Over the past decade, liquid crystalline epoxy (LCER) has attracted much attention as a promising matrix for the development of efficient heat dissipation materials. This study presents a comprehensive study including synthesis, preparation and chacterization of polymer/inorganic composites using typical 4,4-diglycidyloxybiphenyl (DP) epoxy among LECR. To confirm the thermal conductivity of composite materials, we have prepared composite samples composed of epoxy resin and single-wall carbon nanotube (SWCNT) as a filler. In particular, DP composites exhibit higher thermal conductivity than commercial epoxy composites that use the same type of filler due to the highly ordered microstructure of the LCER. In addition, the thermal conductivity of the DP composite can be controlled by controlling the amount of filler. In particular, the DP composite containing a SWCNT content of 50 wt% has the highest thermal conductivity of 2.008 W/mK.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.6
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• pp.694-703
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• 2012

To understand the characteristics of sedimentary and benthic environments in habitats of naturally-occurring intertidal benthic macroalgae, various geochemical parameters of sediment (grain size, ignition loss [IL], chemical oxygen demand [COD], and acid volatile sulfur [AVS]) and pore water (temperature, salinity, pH, and nutrients) were measured in the southern intertidal zone of Hampyeong Bay at two month intervals from April to October 2009. Ecological characteristics including the distribution and biomass of benthic macroalgae were also investigated. Benthic macroalgae were distributed below 4 to 5 m depth from mean sea level near the lower portion of the intertidal zone where air exposure time is relatively short. The distribution area and biomass of benthic macroalgae gradually decreased during the study period. The surface sediments in the benthic algal region were mainly composed of finer sediments, such as slightly gravelly mud and mud. The temperature, salinity, pH, and nutrient concentrations (except dissolved inorganic nitrogen) in pore water did not differ in regions with and without benthic macroalgae, whereas the mean grain size and the concentrations of IL, COD, and AVS in sediments were much higher in regions harboring benthic macroalgae. The correlation between mean grain size and IL in sediments displayed two distinct gradients and the slope was much steeper in regions harboring benthic macroalgae, indicating that the content of organic matter in benthic algal region is not solely dependent on mean grain size. Our results indicate that the benthic macroalgae in the southern intertidal zone of Hampyeong Bay play an important role in the accumulation of organic matter in sediment.

• Korean Journal of Food Science and Technology
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• v.5 no.4
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• pp.258-267
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• 1973

Chemical analysis and enzymatic hydrolysis of certain Korean acorns were performed in order to make use of the local acorns. Exclusion of tannin from acorns is aided in the processing. Studies of these were undertaken and the results obtained are summarized as follows; 1. Several Korean acorns were used to analyze their proximate composition, tannin and major inorganic principles. The content of acorn tannin was found to be 6.5 to 7.5%. 2. An Attempt was made to screen suitable strains in order to make acorn-tannin-hydrolyzing enzyme accumulated in the culture broth, and Aspergillus flavus and Asp. sp. AN-11, which showed in their culture broths, were obtained from the contaminated acorns. 3. Cultural measures for the strains of Aspergillus flavus and Asp. sp. AN-11 for an improved tannase production and optimal conditions were determined.

• Applied Biological Chemistry
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• v.47 no.3
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• pp.332-338
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• 2004

An investigation in search of the best oxidizing agent for smoke generators using rice chaff as a combustible carrier was carried out. Smoke rods formulated with active ingredients (AIs) such as inorganic oxidizing agents, glue, and powdered rice chaff, showed constant and high burning rate and high smoking rate on 11 kinds of pesticides. Sodium chlorate was the most suitable oxidizing agent for smoke rod. Even though the sodium chlorate content of the formulation showing the highest smoking rate of AI was variable to pesticides, the smoking rate appeared to increase as the burning rate increased. Active ingredients in smoke generator using rice chaff as a combustible carrier were stable for 60 days when stored at $50^{\circ}C$. An apparatus designed for smoke trapping was useful to collect smoked active ingredients.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.3
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• pp.275-280
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• 1997

The experiment was carried out to determine Al tolerance ranges of two rice cultivars(Ilpumbyeo and Hyangmibyeo) during germination and early growth. The amount of 0, 300, 600 and 900ppm Al were treated in the germination media. Plant height and root length of rice cultivars were decreased significantly with Al concentration. The reduction of growth was more remarkable in root than in shoot. Germination rates in all Al concentrations were decreased comparing with untreated control. Two rice cultivars were not different in Al concentrations. As Al concentration was increased, chlorophyll content were decreased. Ca and Mg contents in 300ppm of Al treatment were sharply increased. Free proline contents of both rice cultivars grown at the 300, 600, and 900ppm of Al treatments were increased only in the 3 days after Al treatments.