• Applied Chemistry for Engineering
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• v.23 no.5
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• pp.456-461
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• 2012

To verify the utilization of biomass as energy, the combustion characteristic has been studied by an experimental combustion furnace under an isothermal and non-isothermal combustion. The wood pellet, rice straw and rice husk were used as biomass samples in this work. The characteristics of emission gases, dusts and residues from biomass combustion have been analyzed and compared with those of reuse derived fuel (RDF). From isothermal combustion experiments, it was found that the incomplete combustion of rice straw was greater that that of rice husk, wood pellet and RDF. This is due to the fact that the combustion reaction rate of the rice straw was faster than that of other samples, and the oxygen concentration in rice straw combustion was rapidly decreasing. It was also found that $NO_{X}$ concentration of emission gas from wood pellet combustion was the lowest. From non-isothermal combustion experiments, it was found that all samples were burned before $900^{\circ}C$. Also, the temperature range of $NO_{X}$ emission was similar to that of CO emission, on the other hand, $SO_{2}$ was emitted at a higher temperature than that of CO emission.

• Journal of The Korean Society of Grassland and Forage Science
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• v.8 no.3
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• pp.77-84
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• 1988

This experiment was conducted to investigate the morphological and structual characters and the dry weight of plant (DW/pl.) concerned vegetational structure of orchardgrass pastures by the times of year, from 1 year to 7 year previous, 1986 through 1980, alternately. This experiment was carried out on the experimental fields of Yonsei University. The results are summarized as follows: 1. Population density (PD) was extremely decreased by the times of year. 2. Pasture productivity was highest at 3 year old pasture, was lowest at 5 year old pasture and was recovered at 7 year old pasture. 3. Recovery of pasture productivity was followed the increase of dry weight of plant (DW/pl.) and number of tillers per plant (NT/pl.). 4. The population density of 7 year old pasture was 14 plants per square meter. 5. The number of tillers per plant (NT/pl.), dry weight of plant (DW/pl.) piant length (PL), and plant size (PS) was frequently showed the highest values by the times of established year. 6. The stubble diameter (DIA), stubble area (SB), plant size (PS), distance between neibour plant (DIS) and leaf alea index (LAI) was increased according to the times of year. 7. The dry weight of plant (DW/pl.) was positively significant correlations with the number of tillers per plant (NT/pl.) all of the established pastures, but the dry weight of a tiller (WT) was tended to increase of correlations with the dry weight of plant (DW/pl.) by the times of year. 8. Differences between morphological and structual characters was recognized according to the times of year.

• Journal of the Korean Society for Heat Treatment
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• v.30 no.5
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• pp.215-221
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• 2017

The effect of austenitizing temperature on the degree of carbides re-solutionizing, mean graine size, hardness and the volume fraction of retaind austenite ($V_{\gamma}$) etc., has been studied by means of metallography, X-ray diffractometry and hardness measurement in STD 11 tool steel. As austenitizing temperature increases, the amount of alloying elements which is re-dissolved into matrix increases, resulting in increase of $V_{\gamma}$, due to the chemical stabilization of austenite. The Vickers hardness value decreases with increasing austenitizing temperature, which is attributed to grain size as well the volume fractions of $V_{\gamma}$ and carbides. Theoretical diffraction intensity of (200) ${\alpha}^{\prime}$, (211) ${\alpha}^{\prime}$ (200) ${\gamma}$ and (220) ${\gamma}$ peaks obtained by $CuK_{\alpha}$ chracteristics X-ray (${\lambda}=0.15429nm$) was calculated, and quantitative analysis of $V_{\gamma}$ could be carried out by X-ray diffraction method. The resultant value is well coincided with the value obtained by image analysis method. When the quenched specimen is tempered above $200{\sim}400^{\circ}C$ for 30 min, the transition carbides i.e., MC and $M_2C$ in the size of about 20 nm begin to precipitate at $300^{\circ}C$.

• Korean journal of food and cookery science
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• v.18 no.2
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• pp.129-135
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• 2002

The effects of adding green tea powder on the quality and storage characteristics of tofu were studied. As the addition of green tea powder increased, the moisture content of tofu was decreased but those of crude protein and the crude ash were increased. The addition of green tea powder increased the production of whey and consequently decreased the yield of tofu. At the beginning of storage, the pH of the tofu with green tea powder was increased, but decreased rapidly at the eighth day of storage. The pH of tofu-soaking solution was decreased during the storage period. The L and b values showed no significant changes but a value was increased during storage. Textural characteristics of tofu added with green tea powder also did not show significant changes during storage. Although the total plate counts and absorbances of soaking solution of tofu were increased during storage, the samples with 1.0% green tea powder had the lowest TPC (3.0$\times$10$\^$6/ CFU/ml) and the lowest absorbance (0.175) at the eighth day of storage.

• Korean journal of food and cookery science
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• v.8 no.2
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• pp.65-71
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• 1992

The objective of this study was to evaluate the effect of the Seoktanbyung, when the ingredients were changed in a variety aspects; the amount of sweetpersimon flour to rice flour, and the amont of water and several kinds of sweeteners as sugar, syrup and honey. The evaluation of these resul were as followings: 1. The standard recipes of Segktanbyung were that the ratio of 30% of sweetpersimon flour was added to ingredients for it. In case of group of sugar added, 30 g of sugar and 90 ml of water were added, in case of group of syrup added, 40 ml of syrup and 60 ml of water, and in cage of group of honey added, 40 ml of honey and 60 ml of water were added. 2. According to the sensory evaluation, the color, flavor, softness, overall quality of Seoktanbyung were the most excellent the ratio of sweetpersimon flour 30%. The grain was gradually coarsen accrording to incremont of sweetpersimon flour added, but chewiness was gradually diminished. The moistness increase according to increment of sweeteners, sweetness was felt heavily according to gradual increment of sweetpersimon flour and sweeteners. 3. According to Instron evaluation, the hardness, gumminess, adhesiveness and chewiness of Seoktanbyung were shown to significant differences, however, the cohesiveness and springiness of it were not shown to significant differences. 4. The evaluation of colors which were shown that as more sweetpersimon flour was added, lightness was diminished, and ${\Delta}E$ which represents total difference in colors was incresed. 5. The content of moisture in Seoktanbyung is such as; 42.96% in sugar added, 38.73% in syrup added, 37.43% in honey added.

• Fire Science and Engineering
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• v.24 no.3
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• pp.86-92
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• 2010

One of the limitation of wood as building materials is its flammability. The purpose of this paper is to examine the combustion properties of the Pinus rigida and Castanea savita which are grown in Korea and meet the desirable characteristics for use of construction materials. The cone calorimeter (ISO 5660-1) was used to determine the heat release rate (HRR) and fire smoke index, as well as CO and $CO_2$ production and smoke obscuration. The $HRR_{mean}$ of the Castanea savita and Pinus rigida at $50\;kW/m^2$ of radiant heat flux was $70.4\;kW/m^2$ and $68.5\;kW/m^2$. Furthermore, the THR of Castanea sativata was 120.8 MJ/kg and it was higher than the THR of Pinus rigida ($81.9\;MJ/m^$). These results are depend on the bulk density of tested wood species. The Castanea savita has high $CO_{mean}$ yield and high CO/$CO_2$ yield compared with that of Pinus rigida.

• KSBB Journal
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• v.18 no.6
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• pp.490-494
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• 2003

For the production of antifungal compound, strain B-1 was used as a strong producing strain among bacteria isolated from various soil samples. The optimum medium for the production of antifungal compound was PDB (potato starch 0.4%, dextrose 2％, pH5.1). The optimum conditions for the production of antifungal compound didn't affect on the carbon and nitrogen sources. The produced compound showed broad antimicrobial activity to the tested strains such as five fungi and four bacteria. The optimum pH and temperature of the production antifungal compound were pH 5.0 and 28$^{\circ}C$, respectively. Ether extrct (1$\mu\textrm{g}$/${\mu}\ell$) of culture broth was confirmed inhibitory zone by the thin layer chromatography and plate assay. The antimicrobial compound was unstabled after heat (121$^{\circ}C$) trsatment. Strain B-1 was mass cultured in a 5-liter tormentor, containing 3 liters of PDB medium at 28$^{\circ}C$, pH 5.0, 120 (pm with aeration (1L/min).

• Journal of the korean academy of Pediatric Dentistry
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• v.25 no.2
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• pp.292-303
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• 1998

The arbitrary primer polymerase chain reaction(AP-PCR) and Southern blot restriction fragment length polymorphism(RFLP) were used to genotype the cariogenic pathogen S. mutans in children. Following the morphologic chracteristics of colony on selective medium for S. mutans, total genomic DNA from 155 strains was extracted by conventional methods. Among 155 strains, 143 strains (92.3%) were confirmed S. mutans by PCR with dexA gene and 114 strains were used in this study. Three random sequence 10-base oligonucleotide primers were chosen for AP-PCR. The amplified DNA products were separated electrophoretically in a 2% agarose gel containing ethidium bromide and the banding patterns were compared among different strains. For RFLP analysis, DNA was digested with EcoRI and BamHI, separated on a 0.7 % agarose gel and transferred to a nylon membrane. The membrane was probed with a previously characterised 1.6 kilobases (kb) DNA fragment cloned from gtf B gene of S. mutans. The probe was labeled with isotope[$^{32}P-{\alpha}CTP$], and hybridized fragments were detected with intensifying screen. AP-PCR produced 4-8 DNA bands in the 0.25-10 kb regions and distinguished 9, 10 or 12 genotypes, depending on the specific primer used. Southern blot RFLP analysis revealed 2 hybridization patterns consisting of 1 DNA fragments 450, 500 bp. These results indicate that AP-PCR is more discriminative method for genotyping of S. mutans.

• Polymer(Korea)
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• v.25 no.4
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• pp.503-511
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• 2001

Present silica dispersing agents are based mainly on fatty acid derivatives of Zn, K and mixture of fatty acid and metallic soaps are used to increase activity. The viscosity of silica filled rubber is lowered by Zn-K soap type silica dispersing agent, thus fluidity of hydrocarbon chains and processibility is improved. Silica dispersing agent should not exert an influence on chracteristics of vulcanization. But scorch and curing time is shortened by Zn-K soap type silica dispersing agent. A newly developed silica dispersing agent, which is a nonmetal type agent, reduced the viscosity and hardness of silica compounding rubber, and the highly increased degree of dispersion of silica is caused by interaction of silica and rubber. Also it did not affect the curing characteristics and scorch stability of silica compounding rubber.

• Solar Energy
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• v.18 no.3
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• pp.89-94
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• 1998

The heat transfer characteristics of a fluidized bed latent heat storage system using encapsulated PCM was investigated. The cylindrical test section has the dimension of 50 mm I.D. and 40 cm in height. The phase change material(PCM) was the sodium acetate and was encapsulated by the multiple layers of PMMA and paraffin wax. The size of encapsulated PCM was $2{\sim}3mm$ and melting point was $58^{\circ}C$. The instantaneous heat storage and heat release rates were determined and the instantaneous heat transfer coefficient based on the fluidized bed volume was also determined. The effect of inlet temperature and velocity of heat transfer fluid on the heat transfer coefficient was also investigated.