• Clean Technology
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• v.14 no.2
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• pp.144-151
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• 2008

Life cycle assessment was carried out to evaluate the environmental values of dimethylas a diesel alternative fuel with the assumption of dimethyl ether production from natural gas via synthesis gas. The whole life cycles from raw material acquisitions to the final usages of diesel and dimethyl ether were involved in the assessment. Inventory analysis showed that the most significant environmental impacts came from resource depletions and air emissions. Impact assessment revealed that dimethyl ether was environmentally better in the aspect of human health and ecosystem quality but worse in resource depletions compared with diesel fuel. Suggestions for environmental improvement of dimethyl ether as a diesel alternative fuel were prepared based on the assessment results.

• Applied Biological Chemistry
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• v.37 no.5
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• pp.402-408
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• 1994

For the examination of the role of monocerin(1) on the biological activity, (8S, 9S, 11R)-(-)-monocerin(20) and (9S, 11R)-(+)-fusarentin 4, 5-dimethyl ether(19) were synthesized by a condensation of the benzylic anion of ethyl 2, 3, 4-trimethoxy-6-methylbenzoate(16) with modifyed (R)-ethyl 3-hydroxyhexanoate (9). In a key step, bioreduction with active dried baker's yeast in organic solvent system was employed to get a chiral aldehyde 12. Their phytotoxic activities were tested on rice seedlings and lettuce seeds.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.434-437
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• 2021

Canopen over EtherCAT(CoE) is a Canopen protocol that operates based on EtherCAT in industrial sites. In order to analyze a CoE network system and a performance through packet sniffing and reversing, it is necessary to know Data Objects structure and changes of its value. However, since Data Objects in Canopen is dependent on the devices, there is a limitation by using an existing packet analysis program like a Wireshark. Therefore, we designed and developed a system that infers Data Objects structure and system configuration.

• Applied Biological Chemistry
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• v.29 no.2
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• pp.138-147
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• 1986

Barley koji was made in order to investigate the lipid contents of barely koji during preparation. Diethyl ether extracts and 85% methanol extracts were extracted and purified. The lipid components were classified. The individual neutral lipids, glycolipids and phospholipids were fractionted, quantified and fatty acid compositions of the three lipids were determined. Total lipid contents of diethyl ether and 85% methanol extract of barley koji increased during preparation. Neutral lipid, glycolipid and phospholipid contents in diethyl ether extract increased, however, neutral lipid, glycolipid and phospholipid contents in 85% methanol extract decreased during koji preparation. TG content of the neutral lipid in diethyl ether extract decreased. Conversely, DG, FS, FFA and ES contents increased. But TG, DG and FS contents of the neutral lipid in 85% methanol extract decreased. LPC, (PC+PS), PI, PG and PE contents of the phospholipid on diethyl ether extract increased. But LPC, (PC+PS), PE and PI contents in 85% methanol extract decreased during koji preparation. Palmitic acid, linoleic acid and linolenic acid of neutral lipid in diethyl ether extract decreased, however, palmitic, stearic, oleic, linoleic acid in 85% methanol extract decreased. Palmitic acid, stearic acid, oleic acid and linoleic acid of glycolipid in diethyl ether extract increased, but in 85% methanol extract they decreased except oleic acid. Palmitic, stearic, oleic, linoeic and linolenic acid of phospholipid in diethyl ether extract increased during koji preparation. On the other hand palmitic, oleic and linoleic acid in 85% methanol extract decreased but stearic and linoleic acid increased.

• Journal of the Korean Chemical Society
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• v.32 no.5
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• pp.443-451
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• 1988

New crown ether dye-Ⅰ and dye-Ⅱ having an azo group(-N=N-) were synthesized from monobenzo-15-crown-5 and dibenzo-18-crown-6. These dyes showed ${\lambda}_{max}$ of 377 and 383nm respectively. The complexes of alkali metal ions ($Na^+$, $K^+$, $Cs^+$) with dye ligands showed band shift (390~400nm) and intensity increased. For a given anion, the extraction constants are in the order of $K^+$ < $Cs^+$ < $Na^+$ for dye-Ⅰ and $Cs^+$ < $Na^+$ < $K^+$ for dye-Ⅱ. These results show that the selectivity of crown ethers toward the alkali metal ions is dependant on the charge density of cation and the size of crown ether cavity. For a given cation, the order of the extraction constant is $Cl^-$ < $Br^-$ < $I^-$ < picrate. This order coincides with the degree of anion solvation effect.

• Polymer(Korea)
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• v.37 no.2
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• pp.211-217
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• 2013

Potassium tert-butoxide (t-BuOK) with $CO_2$ or benzoyl chloride (BzC) as a polymerization initiator system was used with crown ether or TMAC as catalyst to synthesize very high molecular weight nylon 4 homo- and copolymers by anionic ring opening polymerization. Effect of different amounts of catalyst, crown ether and TMAC on the polymerization was studied in terms of intrinsic viscosity, yield and thermal properties. By adding crown ether or TMAC, polymers with very higher intrinsic viscosity values were obtained in a high yield. It was possible to synthesize nylon 4 homopolymer with such a high intrinsic viscosity value of 6.36 dL/g. Crown ether was found to be more efficient in terms of intrinsic viscosity and polymer yields than TMAC. Thermal analysis confirmed that molecular weight effect on the thermal properties of both nylon 4 and nylon 4 copolymer was marginal.

• Korean Journal of Medicinal Crop Science
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• v.4 no.1
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• pp.31-37
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• 1996

This study was conducted to know the odor characteristics and compounds in neutral, acidic and basic fraction from the essential oil of Valerliana fauriei root. Among the fraction from the essential oil of V. fauriei root, the content of neutral fraction was 92%, that of the acidic fraction, 6%, and that of basic and phenolic fractions, less than 1%, respectively. The neutral fraction was characterized by sweet-balsamic, woody, musky and medicinal odor. The acidic fraction had sweat-socks, valeric-like and cheese-like odor characters. The netural fraction of essential oil was fractionated by solvents with different polarities, resulting in 44% of ethyl ether fraction, 34% of pentane-ethyl ether fraction, 11% of pentane fraction and 11% of methanol fraction. The ethyl ether fraction was characterized by woody and medicinal odor and the pentane-ethyl ether fraction, by sweet-balsamic, woody and herb-like odor. The fractions were fractionated again by different solvents, and 12 chemical components including valeranone, 26 components including bornyl acetate, and 43 components including camphene were identified in the ethyl ether fraction, the pentane - ethyl ether fraction, and pentane fraction, respectively. In the acidic fraction, n-butanoic acid and other 44 components were identified, among which the most abundant ones were 3-methyl butanoic acid(42.1%), dimethoxy-2-propanoic acid(11.5%), and 5-­ethyldihydro-2H-furanone(5.7%).

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.2
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• pp.211-218
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• 2014

Recently, software-based programmable logic controller (PLC) systems, which are implemented in standard PLC languages on general hardware, are gaining popularity because they overcome the limitations of classical hardware PLC systems. Another noticeable trend is that the use of integrated development environment (IDE) is becoming important. IDEs can help developers to easily manage the growing complexity of modern control systems. Furthermore, industrial Ethernet, e.g. EtherCAT, is becoming widely accepted as a replacement for conventional fieldbuses in the distributed control domain because it offers favorable features such as short transmission delay, high bandwidth, and low cost. In this paper, we implemented the extension of open source IDE, called Beremiz, for developing EtherCAT-based real-time, synchronized motion control applications. We validated the EtherCAT system management features and the real-time responsiveness of the control function by using commercial EtherCAT drives and evaluation boards.

• Journal of the Korean Applied Science and Technology
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• v.34 no.2
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• pp.203-209
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• 2017

The propenyl ether-type monomers which are applicable for cationic photo-polymerization were synthesized by the condensation reaction of mono and di-functional alcohol with allyl bromide. To examine photo-curable reactivity, these monomers were combined with cationic photoinitiator to prepare coating composition. As a result, the initial rate of polymerization of POMB in mono propenyl ether type was 10.2, which was relatively lower than BPOB in di-propenyl ethers type. However, POMB containing 1.5mol% photoinitiator almost quantitatively reacted within 90 seconds. In addition, Sulfonium salt type photo-initiators containing long-alkyl group showed good solubility with monomers and apperaed to have comparatively higher rate of polymerization and conversion ratio when applying DPSA and DPST which have high acidity on all monomers.

• Journal of Life Science
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• v.15 no.5 s.72
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• pp.692-695
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• 2005

Antifungal activity of ether and ethylacetate extract from Xanthium strumarium L. were tested against 11 plant pathogens by agar diffusion method. Antifungal activity of the ether and ethylacetate extract showed strong antifungal activity against plant pathogenous fungi, i.e. Phytophthora capsici, Sclerotinia sclerotiorum and Aspergillus niger. The $IC_{50}$ of the ether extract against Sclerotinia sclerotiorum was determined $335{\mu}g/ml$ Antifungal activity of the ether extract from Xanthium strumarium L. showed Rf value=0.87 on TLC plate.