• Computational Structural Engineering
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• v.2 no.2
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• pp.53-62
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• 1989

In recent times, the subterranean caverns for storing crude oils and oil products are increasingly needed. The elasto-VIScoplastic DYNamic finite element analysis program(VISDYN) has been developed in order to investigate dynamic responses of the storage cavity. And validity of the program is studied through a numerical example. Mohr-Coulomb yield criterion is adopted and associated flow rule is assumed. Geometrically nonlinear behaviour is taken into account using a total Lagrangian formulation. In dynamic deformation reponses, the difference between the steady state displacements and the unsteady state ones by the static analysis can be neglected.

• Korean Journal of Microbiology
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• v.9 no.3
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• pp.95-102
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• 1971

The growth characteristics of Candida tropicalis KIST 351 on gas oil substrate under different culture conditions were investigated and the preliminary animal feeding experiments using this yeast as a partial substitute of fish meal was also conducted. The yeast assimilates effectively n-paraffins in gas oil ranging from $C_{16}$ to $C_{16}$ with its maximum cell growth at $33^{\circ}C$ and pH 5.5 with aeration of 3 vvn and agitation of 900 rpm. The optimal concentrations of nitrogen sources, $HK_2PO_4$ and $Na_2HPO$ were 4, 2 and 0.5g/1, respectively. Ferrous sulfate, manganese sulfate and zinc sulfate showed positive effect to cell growth with the optimal range of 5-10 ppm. In the feeding experiment with 3 and 5% incorporation of the gas oil grown yeast, neither adverse effects on growth of chicks nor toxic effect were observed. Protein content of the dried cell was 58.8% and its amino acid composition compared well with other single-cell protein products and FAO reference protein.

• Korean Journal of Pharmacognosy
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• v.28 no.4
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• pp.192-197
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• 1997

As a part of searching for new antitumor agents from natural products, 94 kinds of Chinese plants were extracted with petroleum ether/ether (1:1), ethyl acetate and methanol, successively and their cytotoxicities were evaluated against A549 (human lung carcinoma) cell line. Among them, six kinds of ether extracts, seven kinds of ethyl acetate extracts and one kind of methanol extracts showed significant cytotoxic activities (above 70% inhibition) at a concentration of $50\;{\mu}g/ml$. These results surest that they may be involved in natural sources with possible anticancer activities.

• Bulletin of the Korean Chemical Society
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• v.4 no.4
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• pp.183-188
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• 1983

Two major and two minor polyacetylenes were isolated from fresh white Korean ginseng roots. The petroleum ether-ethyl ether fractions containing the polyacetylene compounds were collected through solvent fractionation, partition and silica gel column chromatography. Further separation of polyacetylenic fractions was proceeded by bonded normal phase HPLC utilizing a moderately nonpolar microparticulate column. The low pressure liquid chromatography was used for the semi-preparative separation. The chemical structures of the two major polyacetylenes separated were determined by UV, IR, $^1H$ NMR, $^{13}C$ NMR, mass spectra and elemental analysis. One of them is identified to be heptadeca-1-en-4, 6-diyne-3, 9, 10-triol, a new structure, and the other is heptadeca-1, 9-dien-4, 6-diyn-3-ol, known as panaxynol.

• 중국학논총
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• no.71
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• pp.151-167
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• 2021

Looking at the economic effects of the Chinese coal industry analyzed in this text, the following results could be drawn. First, according to the analysis result of the influence coefficient of the Chinese coal industry in 2017, it is mainly rural and regional development It was analyzed that it had a great influence on the necessary sectors. Second, the sensitivity coefficient of the Chinese coal industry in 2017 was presented in the order of electricity and heat production and supply, monetary finance and other financial services, business services, refined petroleum and nuclear fuel processing products, wholesale business, and retail business. It is judged that this is more influenced by government policy than by influence coefficient.

• Advances in concrete construction
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• v.16 no.2
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• pp.97-106
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• 2023

This research endeavors to explore the enhancement of workforce economic efficiency through the application of nanotechnology, focusing on its economic implications. The findings of this investigation reveal that in recent years, surging global population growth and escalating demands for products and services have led to excessive resource consumption, resulting in adverse environmental consequences and altering environmental conditions-a phenomenon referred to as the economic growth dilemma. Entrepreneurs and economic stakeholders have begun to recognize the importance of sustainable development and the integration of environmental considerations into the production of goods and services. Within this context, knowledge-based economies have emerged as a driving force for sustainable business practices, particularly in the realm of nanotechnology. The integration of nanotechnology across various industries, including pharmaceuticals, agriculture, environmental management, and the chemical and petroleum sectors, as well as energy distribution, has yielded remarkable results. Consequently, this research aims to investigate the application and integration of nanotechnology in environmentally friendly silver nanoparticle production within select industries. Subsequently, it will examine the far-reaching implications of nanotechnology on economic growth and sustainable development.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.137.1-137.1
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• 2010

For Indonesia, sustainable energy supply is an important factor to preserve the stable economic growth. One important strategy is development of renewable energy, which has not been fully exploited yet. The paper examines the potency of renewable energy in Indonesia. Currently, biomass composes 23% of total primary energy supply, while geothermal and hydropower has a combined share of 3%. But according to the overall potency of renewable energy, hydropower is found to have the highest available resource of 76 GW, followed by biomass and geothermal by 49.81 GW and 28.53 GW, respectively. Although the solar radiation is only at modest level ($4.80kWh/m^2/day$), the tropical all year sunlight can boost the competitiveness of solar photovoltaic and thermal application. As for wind energy, the average speed of 3-6 m/s requires the development of low speed wind turbine. The examination of electricity and petroleum product prices through international comparison for non-OECD countries shows fifth lowest price level for both of petroleum products and electricity for industrial use. As for household electricity price, Indonesia is placed the second among all the countries compared. The energy subsidy and price structure are examined in detail because it could be a source of hindrance to renewable energy promotion. The examination of renewable energy potency in this study could provide insights about recent development of renewable energy in Indonesia. As an outcome of policy examination, the price comparison analysis suggests Indonesia to reduce or even remove the energy subsidies in the long run. These findings can be utilized to formulate effective policies for renewable energy promotion.

• Journal of the Korean Applied Science and Technology
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• v.19 no.4
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• pp.258-264
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• 2002

Pyrolysis of polypropylene(PP) Was performed to find the effects of the pyrolysis temperature(425, 450, 475 and $500^{\circ}C$) and the pyrolysis time(35, 50 and 65minutes), respectively. Conversion and liquid yield obtained during PP pyrolysis continuously increased with the pyrolysis temperature( up to $500^{\circ}C$) and the pyrolysis time(up to 65minutes), especially these were more sensitive to the pyrolysis time at $425^{\circ}C$ than other pyrolysis temperatures. Each liquid product formed during the pyrolysis was classified into gasoline, kerosene, light oil and wax according to the distillation temperature based on the petroleum product quality standard of Korea Petroleum Quality Inspection Institute. The liquid products of PP pyrolysis up to $450^{\circ}C$ were almost same fractions($26{\pm}3$wt.% gasoline, $20{\pm}2$wt.% kerosene and $23{\pm}2$wt.% light oil) except wax($3{\sim}13$wt.%). On the other hand, the pyrolysis of PP from $475^{\circ}C$ to $500^{\circ}C$ produced $26{\pm}3$wt.% wax, $24{\pm}1$wt.% gasoline, $18{\pm}1$wt.% kerosene and $16{\pm}1$wt.% light oil. After all, the main liquid product changed from gasoline to wax with increasing pyrolysis temperature.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.5
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• pp.102-112
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• 2012

The vast stores of biomass available in the worldwide have the potential to displace significant amounts of fuels that are currently derived from petroleum sources. Fast pyrolysis of biomass is one of possible paths by which we can convert biomass to higher value products. The wood pyrolysis oil (WPO), also known as the bio crude oil (BCO), have been regarded as an alternative fuel for petroleum fuels to be used in diesel engine. However, the use of BCO in a diesel engine requires modifications due to low energy density, high water contents, low acidity, and high viscosity of the BCO. One of the easiest way to adopt BCO to diesel engine without modifications is emulsification of BCO with diesel and bio diesel. In this study, a diesel engine operated with diesel, bio diesel (BD), BCO/diesel, BCO/bio diesel emulsions was experimentally investigated. Performance and gaseous & particle emission characteristics of a diesel engine fuelled by BCO emulsions were examined. Results showed that stable engine operation was possible with emulsions and engine output power was comparable to diesel and bio diesel operation. However, in case of BCO/diesel emulsion operation, THC & CO emissions were increased due to the increased ignition delay and poor spray atomization and NOx & Soot were decreased due to the water and oxygen in the fuel. Long term validation of adopting BCO in diesel engine is still needed because the oil is acid, with consequent problems of corrosion and clogging especially in the injection system.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.6 no.1_2
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• pp.27-36
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• 1973

The effect of water activity on degradation of pigments in dried lavers, Porphyra tenera Kjellm. was examined when stored at room temperature for fifty days. Chlorophyll pigment was extracted with methanol-petroleum ether mixture solvent(2:1 v/v), partitioned in ether, and analysed spectrophotometrically at 662 nm as chlorophyll a. The degradation products of chlorophyll were isolated on sugar-starch column(85:15 w/w) with n-propanol-petroleum ether solution(1:200 v/v) as a developing solvent. The isolated green colored zones were analysed individually at the wavelengths of 650, 662, and 667 nm as allomerized product, chlorophyll a retained, and pheophytin formed respectively. Carotenoida were also extracted with the methanol mixture solvent, partitioned in ether, and finally redissolved in acetone after the evaporation of ether in a rotary vacuum evaporator. The total carotenoid content was measured as lutein at 450 nm. From the results, it is noted that the rate of chlorophyll degradation reached a minimum at 0.11 to 0.33 water activity while progressively increased at higher moisture levels resulting in rapid conversion of chlorophyll to pheophytin. At lower activity, autocatalysed oxidizing reaction like allomerization seemed prevailing the acid catalysed conversion reaction. The loss of carotenoid pigment was also greatly reduced at the range of 0.22 to 0.34 water activity with much faster oxidative degradation at both higher and extremely lower moisture levels. These two moisture levels indicated above at which the both pigments exhibited maximum stability are considerably higher than the BET monolayer moisture which appeared 7.91 percent on dry basis at Aw=0.10 calculated from the adsorption isothermal data of the sample at $20^{\circ}C$. The rate of pigment loss in heat treated samples at 60 and $100^{\circ}C$ for 2 hours prior to storage somewhat decreased, particularly at higher moisture levels although the final pigment retention was not much stabilized.