• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.2 no.1
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• pp.37-64
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• 2007

The purpose of this study is verifying which financial property of a venture company listed in KOSDAQ is a primary factor to determine Highly Successful company or Less Successful one. For sampling, I classified 405 venture companies, whose averages for 2005 of 2 standards are In the 30% high/low rank, as Highly Successful/Less Successful companies subject to the higher Operating Income to Total Assets and Return on Invested Capital (ROIC), the Highly Successful company. And I verified which variable is most important one to distinguish between Highly Successful companies and Less Successful ones among 24 financial ratios selected through preceding studies. For the analysis, I firstly extracted analogous variables by Stepwise Method and secondly carried out Multi variate Discriminant Analysis. The result mainly shows variables related to returns and stability similar to preceding studies. Especially, Operating Income to Total Assets reveals most reliable variable distinguishing between Highly Successful company and Less Successful one, whereas Current Ratio does not. When reliability of function formula of variables were compared with Operating Income to Total Assets standard and ROIC standard, there was almost no difference.

• Korean Chemical Engineering Research
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• v.51 no.3
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• pp.319-324
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• 2013

The partial oxidation reaction of methane was investigated to produce syngas with $Ni/CeO_2-ZrO_2$, $Ni-Ru/CeO_2-ZrO_2$ and $Ni-Pd/CeO_2-ZrO_2$ catalysts. Honeycomb metallic monolith was applied in order to obtain high catalytic activity and stability in partial oxidation reforming. The catalysts were characterized by XRD and FE-SEM. The influence of various catalysts on syngas production was studied for the feed ratio (O/C), GHSV and temperature. Among the catalysts used in the experiment, the $Ni-Pd/CeO_2-ZrO_2$ catalyst showed the highest activity. The 99% of $CH_4$ conversion was obtained at the condition of T=$900^{\circ}C$, GHSV=10,000 $h^{-1}$ and feed ratio O/C=0.55. It was confirmed that $H_2$ yield increased slightly as O/C ratio increased, while CO yield remained almost constant. Also, $CH_4$ conversion decreased as GHSV increased. It was found that the safe range of GHSV for high $CH_4$ conversion was estimated to be less than 10,000 $h^{-1}$.

• The Korean Journal of Pesticide Science
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• v.9 no.4
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• pp.411-421
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• 2005

This study was carried out to establish rational methodologies for the use of pesticide formulations to be sprayed after water-dilution. Hardness and electric conductivity of six major river water and ground water sampled from 52 sites in major rice-growing areas across the country ranged from 5 to 324 ppm(av. 90 ppm) and from 0.038 to 1.078 dS/m(av. 0.265 dS/m), respectively, which are acceptable for diluent water of pesticides. The pH changes in pesticide spray solutions with time after preparation mainly depended on the pH of the water used for pesticide dilution. The surface tensions of pesticide spray solutions reduced slightly with time after preparation, irrespective of kinds of pesticide formulations. Suspensibility of WPs became worse with an increase in the hardness and salt concentrations of diluent water, even though the degree was negligible. Emulsion stability of ECs became worse with an increase in hardness and salt concentrations of diluent water. Degradation rates of the active ingredients of pesticide spray solutions 3 days after preparation were less than 5%, regardless of mixing or non-mixing of two or more pesticides. Consequently, the spray solutions of most pesticides were usable until two to three days after preparation unless physical properties deteriorated. The tank-mixing order of EC and WP formulations did not make any differences in all the physical properties of pesticide spray solutions. However, the proper order for the tank-mixing of compatible pesticides was WP, WG, SC, EC, and SL, because the order is easy to prepare the pesticide spray solutions. The efficacy of pesticide spray solutions on the respective target pathogens and insect pests of rice plants three days after preparation was recorded over 95% of that of 0 day, which was almost the same as that of the solutions applied punctually after preparation.

• Polymer(Korea)
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• v.33 no.1
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• pp.58-66
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• 2009

The thermotropic liquid crystalline behavior of the homologous series of cellulose tri[4-{4'-(nitrophenylazo) phenoxycarbonyl}] alkanoates (NACEn, n=2$\sim$8, 10, the number of methylene units in the spacer) have been investigated. All of the homologoues formed monotropic nematic phases. The isotropic-nematic transition temperature ($T_{iN}$) decreased when n is increased up to 7, but it became almost constant when n is more than 7. The plot of transition entropy at $T_{iN}$ against n had a sharp negative inflection at n=7. The sharp change at n=7 may be attributed to the difference in arrangement of the side groups. The melting temperature ($T_m$) and associated entropy change at $T_m$, in contrast with $T_{iN}$ and associated entropy change at $T_{iN}$, exhibited a distinct odd-even effect, suggesting that the average shape of the side chains in the crystalline phase is different from that in the nematic phase. The thermal stability and degree of order of the nematic phase observed for NACEn were significantly different from those reported for the homologous series of side-chain and combined type liquid crystal polymers bearing azobenzene or biphenyl units in the side chains. The results were discussed in terms of the differences in the chemical structure, the flexibility of the main chain, the mode of chemical linkage of the side group with the main chain, and the number of the mesogenic units per repeating unit.

• Proceedings of the Korean Society of Life Science Conference
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• 2001.06a
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• pp.67-86
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• 2001

A strain producing strongly fibrinolytic enzyme was isolated from soil and was identified to be Bacillus subtilis by biochemical and physiological characterization. The optimal culture conditions for the production of fibrinolytic enzyme was determined to be 1.0% tryptone, 1.5% soluble starch, 0.5% Peptone, 0.5% NaCl, $(NH_{4})_{3}PO_4.3H_{2}O, and MgSO_{4}.7H_{2}O.$ Initial pH and temperature were pH 8.0 and $30^{\circ}C$ , respectively, The highest enzyme production was observed at 30 hours of cultivation at $30^{\circ}C$ The fibrinolytic enzyme was purified to homogeneity by DEAE Sephadex A-50 ion exchange column chromatography, 70% ammonium sulfate precipitation, Sephadex G-200 and G-75 gel filtration column chromatography. The molecular weight of the purified enzyme was 28,000 as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. A gene encoding the fibrinolytic enzyme was cloned into a plasmid vector pBluescript, transforming E.coli XL-1 Blue. The clone was able to degrade fibrin, This indicated that the gene could encode a fibrinolytic enzyme. The nucleotide sequence of the 2.7 kb insert was determined in both direction. One open reading frame composed of 1023 nucleotides was found to be a potential protein coding region. There was the putative Shine-Dalgano sequence and TATA box upstream of the open reading frame. The homology search data in the genome database showed that both the 2.7 kb insert and 1 kb open reading frame carried no significance in the nucleotide sequence of known fibrinolytic enzyme from Bacillus serovars. The recombinant cell harboring the novel gene involved in fibrinolysis was subjected to protein purification. The molecular mass of the purified fibrinolytic enzyme was determined to be 31864 Dalton, which was highly in accordance with the molecular mass(33 kDa) of the fibrinolytic gene deduced from the insert. The fibrinolytic enzyme was Purified 50.5 folds to homogeneity in overall yield of 10.7% by DEAE Sephadex A-50 ion exchange, 85% ammonium sulfate precipitation, Sephadex G-50, Superdex 75 HR FPLC gel filtration. In conclusion, a novel fibrinolytic gene from Bacillus subtilis was identified and characterized by cloning a genomic library of Bacillus subtilis into pBleuscript. For the soybean fermented by this strain, it is found that there increased assistant protein about 20% compared to the soybean not fermented and increased about 30% according to amino acid analysis and, in particular, essential amino acid increased about 40%. When keeping this fermented soybean powder at room temperature for about 70days, it showed very high stability maintaining almost perfect activity and, therefore, it gave us great suggestion its possibility of development as a new functional food.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.3
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• pp.171-177
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• 2010

As concrete structures are exposed to chemical substances, damaged from salt, or progressed to the neutralization, the surface damage of the structures is generated timely fashion, resulting shortened service life. Especially, the sulfate erosion causes rapid surface defects, and the steel skeleton becomes corroded due to the water infiltration, generating stability deterioration of the concrete structure. In this study, the physical characteristics of the acid-resistant mortar with aluminosilicates was investigated in order to resolve problems of the acid resistance, one of the most serious problems of the cement type repair material. As the result of the experiment, the test specimen turned to exhibit almost equivalent physical characteristics with those of concrete sectional repair materials in terms of compressive and bending strengths. As both the cement sectional repair material and the test specimen were immerged in sulfuric acid solution to examine weight changes, the test specimens exhibited only 4% loss of their weights while the cement sectional repair materials reached at the level of 80% or above, proving the excellence acid resistant characteristics of the test specimens. Consequently, the physical characteristics of acid resistant mortar with aluminosilicates were revealed to be superior than those of concrete sectional repair materials. It can be utilized as a sectional repair material where the acidic erosion is anticipated.

• Polymer(Korea)
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• v.33 no.2
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• pp.144-152
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• 2009

The thermal and optical properties of poly {1-(cholesteryloxycarbonylalkanoyloxy) ethylene}s (PCALEn, n=2$\sim$8,10, the number of methylene units in the spacer) were investigated. All of the homologues formed monotropic cholesteric phases with left-handed helical structures. PCALEn with n=2 or 10, in constrast with PCALEn with $3{\leq}n{\leq}8$, did not display reflection colors over the full cholesteric range, suggesting that the helical twisting power of the cholesteryl group highly depends on the length of the spacer connecting the cholesteryl group to the polyethylene chain. The glass transition temperatures decreased with increasing n. The isotropic-cholesteric phase transition temperatures decreased with increasing n up to 7 and showed an odd-even effect. However it became almost constant when n is more than 7. This behavior is rationalized in terms of the change in the average shape of the side chain on varing the parity of the spacer. This rationalization also accounts for the observed variation of the entropy gain for the clearing transition. The thermal stability and degree of order in the mesophase and the temperature dependence of the optical pitch observed for PCALEn were significantly different from those reported for cellulose tri(cholesteryloxycarbonyl)alkanoates. The results were discussed in terms of the differences in the chemical structure and flexibility of main chain and the number of the mesogenic units per repeating unit.

• Clean Technology
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• v.27 no.4
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• pp.277-290
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• 2021

A supercapacitor, also called an ultracapacitor or an electrochemical capacitor, stores electrochemical energy by the adsorption/desorption of electrolytic ions or a fast and reversible redox reaction at the electrode surface, which is distinct from the chemical reaction of a battery. A supercapacitor features high specific power, high capacitance, almost infinite cyclability (~ 100,000 cycle), short charging time, good stability, low maintenance cost, and fast frequency response. Supercapacitors have been used in electronic devices to meet the requirements of rapid charging/discharging, such as for memory back-up, and uninterruptible power supply (UPS). Also, their use is being extended to transportation and large industry applications that require high power/energy density, such as for electric vehicles and power quality systems of smart grids. In power generation using intermittent power sources such as solar and wind, a supercapacitor is configured in the energy storage system together with a battery to compensate for the relatively slow charging/discharging time of the battery, to contribute to extending the lifecycle of the battery, and to improve the system power quality. This article provides a concise overview of the principles, mechanisms, and classification of energy storage of supercapacitors in accordance with the electrode materials. Also, it provides a review of the status of recent research and patent, product, and market trends in supercapacitor technology. There are many challenges to be solved to meet industrial demands such as for high voltage module technologies, high efficiency charging, safety, performance improvement, and competitive prices.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.2
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• pp.152-160
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• 2021

Converter steel slag(BOF slag) is a vast amount of solid waste generated in the steelmaking process which has very low utilization rate in Korea. Due to the presence of free CaO which can derive bad volume stability in BOF slag, it usually land filled. For recycling BOF and identify its applicability as fine aggregate, this study investigates the fundamental characteristics of mortar with cement replaced ferronickel slag(FNS), which has the potential to be used as a binder. The results suggest that the mineral phases of BOF slag mainly include larnite(CaSiO₄), mayenite(Ca₁₂Al₁₄O₃₃) and wuestite(FeO) while olivine crystallines are shown in FNS. The results of flow and setting time reveals that the flowability and process of hardening increased when the amount of FNS and BOF slag incorporated was increased. The length change shows that the amount of change in the length of the mortar was almost constant regardless of mix proportion while compressive strength was reduced. Micro structure test results revealed that FNS or/and BOF slag mix took a long time to react in the cement matrix to form a complete hydration products. To achieve the efficient utilization of B OF slag as construction materials, proper replacement rate is necessary.

• The Journal of Engineering Geology
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• v.29 no.1
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• pp.23-35
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• 2019

Landslides occur due to heavy rainfall in the summer season. Some of water may infiltrate into the ground; it causes a high saturation condition capable of causing a landslide. Soil properties are crucial in estimating slope stability and debris flow occurrence. The main study areas are Gwanaksan, Suraksan and Bukhansan (Mountain) in Seoul. A total of 44 soil samples were taken from the study area; and a series of geotechnical tests were performed. Physical and mechanical properties were obtained and compared based on region. As a result, among well-graded soils, they are classified as a clayey sand. Coarse-grained and fine-grained contents are approximately 95% and 5%, respectively, with very low amount of clay content. Density, liquid limit and dry unit weight are ranged in $2.62{\sim}2.67g/cm^3$, 27.93~38.15% and $1.092{\sim}1.814g/cm^3$. Cohesion and internal friction angle are 4 kPa and $35^{\circ}$ regardless of mountain area. Coefficient of permeability is varied between $3.07{\times}10^{-3}{\sim}4.61{\times}10^{-2}cm/sec$; it means that it results in great seepage. Permeability is inversely proportional to the uniformity coefficient and is proportional to the effective particle size. In the formal case, there was a difference by mountain area, while in the latter, the tendency was almost similar.