• Journal of Radiation Protection and Research
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• v.21 no.1
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• pp.9-16
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• 1996

For the determination of radiostrontium, $^{89}Sr\;and\;^{90}Sr$ in environmental soil sample, a solvent extraction method for the separation of Ca and Sr from matrix using crown ether was investigated. In comparison with the existing fuming nitric acid method, the extraction method showed high chemical yield of strontium and provided simple and rapid analytical steps. The new analytical method applied to the determination of radiostrontium in some soil sample around a nuclear power station to show that the analytical procedure is readily applicable to the practical radioactivity monitoring.

• Journal of Korea Foresty Energy
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• v.20 no.2
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• pp.1-8
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• 2001

The 90% methanol extracts of eight magnoliaceae plants were collected and tested the cytotoxicity against SK-OV-3 and SiHa cells. Also six pure compounds such as magnonol, honokiol, dihydroxybiphenyl ether, linodenine, anonaine, asimilobine which were previously isolated from Magnolia obovata Thunb. were evaluated the cytotoxicities and their mechanism study using the Lactate dehydrogenase assay(LDH) and FACScan analysis system. Of the tested six compounds, magnonol, honokiol, dihydroxybiphenyl ether showed high cytotoxicities against human cancer cell lines, SK-OV-3 and SiHa cells. In addition, one of the plausible mechanisms of their antitumor activities suggested that they could induce the early stage of apoptosis. For the quantitative analysis, the methanol extractives were fractionated with chloroform, ethylacetate, $H_2O$ and then the ethylacetate fraction was chromatographed on silica gel using n-Hexane ; Acetone(4:1, v/v) as eluent. This fraction was subjected for the quantitative analysis in the HPLC system. The result suggested that the methanol extractives of Magnolia obovata Thunb. contained with magnonol, honokiol, dihydroxybiphenyl ether, 0.9%, 0.3% and 0.24%, respectively.

• Polymer(Korea)
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• v.26 no.1
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• pp.1-8
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• 2002

In this study, poly(arylene ether sulfone) (PAES) having thermal stability and excellent mechanical properties was synthesized to be useful for the matrix of anion exchange resin. $1^{\circ}$-Aminated poly(arylene ether sulfone) ($1^{\circ}$-APAES) was prepared by reduction reaction after lithiation of PAES. Then $3^{\circ}$-APAES was Prepared by alkylation of the amino group of $1^{\circ}$-APAES. The structures of PAES and APAESs were confirmed with FT-IR and $^1H-NMR$ spectroscopy. Also, thermal properties of the resins were characterized by DSC and TG analysis. The introduction of amine groups in PAES resulted in the increase of glass transition temperature and decrease of initial thermal degradation temperature. The ion exchange capacities of $1^{\circ}$-APAES and $1^{\circ}$-APAES were 1.19 and 1.45 meq/g, respectively.

• Journal of Ginseng Research
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• v.10 no.2
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• pp.141-150
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• 1986

This study was attempted to screen the cytotoxic activity of petroleum ether ex- tract from panax ginseng root against human colon cancer cells. Two extracts of panax ginseng root, crude and partially purified, were used for this experiment. The crude extract was prepared by extraction with petroleum ether using Soxhlet aparatus for 12 to 15 hours from panax ginseng and the extract was partially purified by silicic acid column with mixture of petroleum ether: ethyl ether (70 : 30, v/v). Three species of human colon cancer cells, HRT-18, HCT-48 and HT-29, were maintained in DMEM (Dulbecco's modified Eagle medium), and the cells were cultured in DMEM containing serial concentration of the crude or partially purified fraction to observe the cytotoxic activity of the both extracts. The effects of incubation time and concentration of the both extracts in culture medium against the growth of the each cancer cell were determined. The results obtained are summarized as follows: 1. The doubling times of the HRT-18, HCT-48 and HT-29 cells were about 20, 24 and 22 hours, respectively. 2, The inhibitory effects of the crude extract on the growth of cancer cells were increased according to the rise of concentration of the extract and incubation time. 3. The inhibitory effect of partially purified fraction on the growth of HRT-18 cell was about 4 times stronger than that of the crude extract under same experimental condition. 4 The inhibitory effects of the crude and purified fraction on the growth of each cancer cell were shown difference by the kind of the cancer cell. In view of the above results, it could be said that the petroleum ether extract of panax ginseng root inhibited the division of the human colon cancer cell, in vitro.

• Korean Journal of Food Science and Technology
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• v.24 no.5
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• pp.423-427
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• 1992

The volatile components were extracted from kumquat(Fortunella margarita) by simultaneous steam distillation-extraction method and fractionated on silica gel column. The total volatile oil was eluted off first by n-pentane and eluted again by diethyl ether. The total volatile oil and diethyl ether fraction were analyzed by GC and GC-MS. In the total volatile oil, 10 components were identified, of which major ones were limonene(96.5%, of total volatile oil), ${\beta}-pinene$(1.93%) and ${\alpha}-terpineol$(0.42%) and then the characteristic aroma of kumquat appeared to be due to limonene. On the other hand diethyl ether fraction, from which 46 components were identified, contained 9 alcohols, 22 terpenes and terpene alcohols, 7 aldehydes and ketones, 7 esters and 1 miscellaneous components. The major components were ${\alpha}-terpineol$(31.98% of diethyl ether fraction), ${\beta}-terpineol$(7.37%), geranyl acetate(9.69%) and p-menthadien-9-ol(4.12%).

• The Korean Journal of Physiology
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• v.5 no.1
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• pp.11-14
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• 1971

In an attempt to observe possible effects of ether and halothane anesthesia on the protein contents of the lung and liver of rabbits, the animal was subjected to the moderato anesthesia with either ether or halothane by non-rebreathing system for one hour, and the protein content of the lung and liver was measured by the method of Lowry et at. using Folin-phenol reagent. The comparison was made with the protein content from the normal rabbits, and the following results were obtained. l) The protein contents of the lung and liver of the normal rabbit were $45.0{\sim}11.5\;mg/gm$ wet wt. and $100.4{\sim}15.1\;mg/gm$ wet wt. respectively. 2) In the ether or halothane anesthesized group, the protein contents of the lung were $57.2{\sim}13.3\;and\;60.3{\sim}7.2$ respectively. 3) In the anesthesia groups with ether and halothane, the protein contents of the liver were $103.4{\sim}10.0\;and\;90.1{\sim}13.0$ respectively. 4) No significant difference in the protein contents of the lung and liver was observed after ether or halothane anesthesia comparing with the normal.

• Membrane Journal
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• v.25 no.6
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• pp.515-523
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• 2015

While commercial polystyrene-based ion exchange membranes have simple manufacturing processes, they also possess poor durability due to their brittleness. Poly(ethylene glycol)methyl ether methacrylate with hydrophilic side chains of poly(ethylene glycol) was used as a co-monomer to make the membranes have improved flexibility. Hydrophilicity/hydrophobicity of the anion exchange membranes were able to be adjusted by varying the chain lengths of the poly(ethylene glycol). For the preparation of the anion exchange membranes, a porous PE substrate was immersed into monomer solutions and thermally polymerized. The prepared membranes were subsequently reacted with trimethylamine to produce anion exchange functional groups, Quaternary ammonium salts. The prepared pore-filled anion exchange membranes were evaluated in terms of ion exchange capacity, electric resistance, elongation at break and water uptake.

• Journal of Convergence for Information Technology
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• v.9 no.8
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• pp.45-52
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• 2019

This paper proposes the design of a closed-loop stepping motor drive for real-time Ethernet (RTE), which can be easily applied to a variety of RTE protocols. The proposed design is divided into a closed-loop step motor drive which can be reused for various types of RTE protocol and RTE module developed for each specific RTE protocol. It is based on a layered architecture so that the motion control algorithm can be easily reused independently of the RTE protocol and motion profile. To verify the proposed design, closed-loop motor drives based on EtherCAT and Mechatrolink III were developed and their performances were evaluated. Cycle time was measured to verify the real-time communication performance of the developed EtherCAT and Mechatrolink III based motor drive. As a result, the EtherCAT was 7.5 times faster than the Mechatrolink III when 32 motor drives were connected.

• Korean Journal of Materials Research
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• v.34 no.5
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• pp.223-234
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• 2024

This review explores the potential of pillared bentonite materials as solid acid catalysts for synthesizing diethyl ether, a promising renewable energy source. Diethyl ether offers numerous environmental benefits over fossil fuels, such as lower emissions of nitrogen oxides (NO_x) and carbon oxides (CO_x) gases and enhanced fuel properties, like high volatility and low flash point. Generally, the synthesis of diethyl ether employs homogeneous acid catalysts, which pose environmental impacts and operational challenges. This review discusses bentonite, a naturally occurring alumina silicate, as a heterogeneous acid catalyst due to its significant cation exchange capacity, porosity, and ability to undergo modifications such as pillarization. Pillarization involves intercalating polyhydroxy cations into the bentonite structure, enhancing surface area, acidity, and thermal stability. Despite the potential advantages, challenges remain in optimizing the yield and selectivity of diethyl ether production using pillared bentonite. The review highlights the need for further research using various metal oxides in the pillarization process to enhance surface properties and acidity characteristics, thereby improving the catalytic performance of bentonite for the synthesis of diethyl ether. This development could lead to more efficient, environmentally friendly synthesis processes, aligning with sustainable energy goals.

• The Korean Journal of Pesticide Science
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• v.10 no.2
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• pp.124-130
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• 2006

Rice plant extracts of brown planthopper (BPH) resistant rice varieties, Jangseongbyeo (JSB) and Hwacheongbyeo (HCB) at different growth stages (seedling, tillering, heading and ripening) were sequentially fractioned using hexane, ethyl ether, ethyl acetate, butanol, and distilled water. The extracts were applied to BPH susceptible rice variety, Dongjjnbyeo (DJB), to investigate the insecticidal and repellent effects against BPH. BPH insecticidal effects were not clearly observed with almost all of the extract fractions obtained from both JSB and HCB varieties for 12 h, whereas the ethyl ether and hexane extract fractions showed about 10 to 30% of BPH mortality in 24 to 48 h of application periods. An effective BPH repellent activity was found with the applications of ethyl ether extract fractions obtained from JSB variety. The extract fractions obtained from HCB variety did not show any different repellence among the various fractions. The BPH repellent effects of the extract fractions obtained at different growth stages of either JSB or HCB varieties did not show any correlations. The effect of ethyl ether fraction on BPH repellent was continually increased by 30 h after treatment and thereafter decreased. In addition, the first sub-fraction separated by a flash column chromatography eluted with chloroform:methanol (9:1, v/v) from the BPH effective ethyl ether faction in JSB variety might be meaningful to repel BPH from BPH susceptible target rice plants. The results indicated that the ethyl ether fraction obtained from JSB was higher in repellent activity than in insecticidal activity, and suggesting that there might be specific substance(s) in the first sub-fraction (sF1) of the ethyl ether fraction in JSB that could provide repellent activity against BPH.