• Journal of the Korean Chemical Society
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• v.38 no.3
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• pp.254-259
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• 1994

Five new crown ethers containing methyl groups were synthesized. 2,3,4,5: 9,10,11,12-Dibenzo-8,8-dimethyl-15,18,1-trioxacycloeicosane, 2,3,4,5: 9,10,11,12-dibenzo-8,8-dimethyl-15,18,21,1-tetraoxacyclotricosane, 2,3,4,5 : 9,10,11,12-dibenzo-8,8-dimethyl-15,18,21,24,1-pentaoxacyclohexacosane, 2,3,4,5 : 9,10,11,12 : 22,23,24,25 : 29,30,31,32-tetrabenzo-8,8,28,28-tetramethyl-15,18,21,35,38,1-hexaoxacyclotetracontane and 2,3,4,5 : 9,10,11,12 : 25,26,27,28:32,33,34,35-tetrabenzo-8,8,31,31-tetramethyl-15,18,21,24,38,41,44,1-octaoxacyclohexatetracontane were synthesized by reaction of 4,4'-isopropylidenediphenol with di-, tri-and tetraethyleneglycol ditosylate in the presence of MOH(M = Na, K). Di-, tri- and tetraethyleneglycol ditosylate were synthesized by reaction of p-toluenesulfonylchloride with diethyleneglycol, triethyleneglycol and tetraethyleneglycol in the presence of NaOH.

• Journal of Pharmaceutical Investigation
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• v.24 no.4
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• pp.273-279
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• 1994

The stability of three oximes, Hl-6 [(4-carbamoyl-2'[(hydroxyimino)-methyl]- 1,1'-oxydimethylenedi-(pyridinium chloride)], Hl-CN [(4 cyano-2'-[(hydroxyimino)-methyl] -1,1'-oxydimethylene-di-(pyridinium chloride)], and 2-PAM [pralidoxime chloride] in aqueous solutions was evaluated by HPLC assay. The rate of degradation is dependent on the pH as well as the temperature at which the solution is stored. The optimum pH for the stability of these oximes was pH 2 to 3. The degradation rate constant for 2-PAM ($k\;at\;70^{\circ}C$, $2.07{\times}10^{-4}/hr;\;E_a\;value$, 27.2 kcal/mol) was smaller than those for bis-pyridiniumoximes, Hl-6 ($k\;at\;70^{\circ}C$, $3.38{\times}10^{-3}/hr$) and Hl-CN ($k\;at\;70^{\circ}C$, $8.66{\times}10^{-3}/hr;\;Ea\;value$, 20.7 kcal/mol). In mechanistic analyses, it was found that Hl-CN was decomposed through not only the hydrolysis of nitrile group but also the cleavage of methylene ether bridge, in contrast to Hl-6 which was degraded mainly through the cleavage of methylene ether bridge.

• Advances in Traditional Medicine
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• v.8 no.3
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• pp.222-227
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• 2008

Citrus aurantium var. amara L., commonly known as 'bitter orange' or 'sour orange', of the family Rutaceae, has traditionally been used in the treatment of various ailments, and it possesses different types of pharmacological properties. As a part of our on-going studies on the plantsfrom the Iranian flora, the extract of C. aurantium var. amara has been studied for its weight lossproperties using the mice model. While the Sep-Pak fraction, 20% methanol (MeOH) in water, of the hydro-methanolic extract of the peels of C. aurantium var. amara fruits, when injectedintraperitoneal (i.p.) at a dose of 10 mg/kg, significantly decreased the level of weight gain of the mice in comparison with control the group (P < 0.01), the Sep-Pak fraction 80% MeOH in water decreased the initial weight of mice by 0.44% in six weeks. The administration of the total extract(10 and 20 mg/kg, i.p.), and the Sep-Pak fractions, 40% and 60% MeOH in water (10 mg/kg, i.p.)did not show any significant change of weight of the test mice. Of the two active fractions, the80% MeOH in water fraction did not show any noticeable adverse effects on mice, and was therefore analysed by reversed-phase preparative high performance liquid chromatography resulting in the isolation and identification of four major components, two coumarins, meranzin hydrate (1) and bergamottin (2), and two flavonoids, xanthomicrol 5,4'-di-methyl ether (tangeritin, 3) and hymenoxin 5,7-di-methyl ether (nobiletin, 4).

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.3
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• pp.54-62
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• 2007

The knock characteristics in an engine were investigated under homogeneous charge compression ignition (HCCI) operation. Liquefied petroleum gas (LPG)and gasoline were used as fuels and injected at the intake port using port fuel injection equipment. Di-methyl ether (DME) was used as an ignition promoter and was injected directly into the cylinder near compression top dead center (TDC). A commercial variable valve timing device was used to control the volumetric efficiency and the amount of internal residual gas. Different intake valve timingsand fuel injection amounts were tested to verify the knock characteristics of the HCCI engine. The ringing intensity (RI) was used to define the intensity of knock according to the operating conditions. The RI of the LPG HCCI engine was lower than that of the gasoline HCCI engine at every experimental condition. The indicated mean effective pressure (IMEP) dropped when the RI was over 0.5 MW/m2and the maximum combustion pressure was over 6.5MPa. There was no significant relationship between RI and fuel type. The RI can be predicted by the crank angle degree (CAD) at 50 CA. Carbon monoxide (CO) and hydrocarbon (HC) emissions were minimized at high RI conditions. The shortest burn duration under low RI was effective in achieving low HC and CO emissions.

• Journal of Korea Society of Industrial Information Systems
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• v.24 no.5
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• pp.9-16
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• 2019

In today's global energy market, the importance of green energy is emerging. Hydrogen energy is the future clean energy source and one of the pollution-free energy sources. In particular, the fuel cell method using hydrogen enhances the flexibility of renewable energy and enables energy storage and conversion for a long time. Therefore, it is considered to be a solution that can solve environmental problems caused by the use of fossil resources and energy problems caused by exhaustion of resources simultaneously. The purpose of this study is to efficiently produce hydrogen using plasma, and to study the optimization of DME reforming by checking the reforming reaction and yield according to temperature. The research method uses a 2.45 GHz electromagnetic plasma torch to produce hydrogen by reforming DME(Di Methyl Ether), a clean fuel. Gasification analysis was performed under low temperature conditions ($T3=1100^{\circ}C$), low temperature peroxygen conditions ($T3=1100^{\circ}C$), and high temperature conditions ($T3=1376^{\circ}C$). The low temperature gasification analysis showed that methane is generated due to unstable reforming reaction near $1100^{\circ}C$. The low temperature peroxygen gasification analysis showed less hydrogen but more carbon dioxide than the low temperature gasification analysis. Gasification analysis at high temperature indicated that methane was generated from about $1150^{\circ}C$, but it was not generated above $1200^{\circ}C$. In conclusion, the higher the temperature during the reforming reaction, the higher the proportion of hydrogen, but the higher the proportion of CO. However, it was confirmed that the problem of heat loss and reforming occurred due to the structural problem of the gasifier. In future developments, there is a need to reduce incomplete combustion by improving gasifiers to obtain high yields of hydrogen and to reduce the generation of gases such as carbon monoxide and methane. The optimization plan to produce hydrogen by steam plasma reforming of DME proposed in this study is expected to make a meaningful contribution to producing eco-friendly and renewable energy in the future.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.3270-3275
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• 2007

DME (Dimethyl Ether, $CH_3OCH_3$) has highly attracted attention as an alternative fuel for transportation, power generation and LPG substitute owing to its easy transportation and cleanliness. This study was conducted to verify the combustion performance and to identify potential problems when DME is fuelled to a gas turbine. GE7EA gas turbine of Pyong-Tak power plant was selected as a target to apply the DME. Combustion tests were conducted by comparing DME with methane, which is a major component of natural gas, in terms of combustion instability, $NO_X$ and CO emissions, and the outlet temperature of the combustion chamber. The results of the performance tests show that DME is very clean but has a low combustion efficiency in low load condition. From the results of the fuel nozzle temperature we have ascertained that DME is easy to flash back, and this property should be considered when operating a gas turbine and retrofitting a burner.

• Journal of ILASS-Korea
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• v.18 no.4
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• pp.188-195
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• 2013

An investigation on spray characteristics of fuels which diesel and di-methyl ether (DME) with change of injection pressure used the multi-injection in constant volume combustion chamber (CVCC). Diesel was already used famous fuel which we could use. DME showed similar features with diesel like as cetane number, auto-ignition temperature. High cetane number of diesel and DME could make possible to compression ignition. DME showed different atomization from diesel due to evaporating pressures and boiling points. Experiments were carried out in CVCC equipped with Delphi solenoid 6-hole type injector and the spray characteristics of diesel and DME were tested the various pre and pilot injection. Terms of injections and a number of injections in multi-injection has been controlled. Experiments were performed in 2 types that 1500 rpm, 2000 rpm and under the condition of injection ranging from 100 bar to 500 bar. From the results of this experiment diesel showed longer spray penetration than DME. That result showed different of atomization speed DME and diesel. Result of high injection pressure condition showed similar spray characteristics diesel and DME. After this investigation, new conditions and experiments using laser light to go forward and add the fuels like as the biodiesel and diesel and DME blend.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.4
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• pp.32-39
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• 2009

The HCCI engine is a next generation engine, with high efficiency and low emissions. The engine may be an alternative to SI and DI engines; however, HCCI's operating range is limited by an excessive rate of pressure rise during combustion and the resulting engine knock in high-load. The purpose of this study was to gain a understanding of the effect of only initial temperature and thermal stratification for reducing the pressure-rise rate in HCCI combustion. And we confirmed characteristics of combustion, knocking and emissions. The engine was fueled with Di-Methyl Ether. The computations were conducted using both a single-zone model and a multi-zone model by CHEMKIN and modified SENKIN.

• Natural Product Sciences
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• v.14 no.4
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• pp.281-288
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• 2008

From the MeOH extract of the whole plants of Lathyrus davidii (Fabaceae), thirteen constituents were isolated and identified as the flavonoids astragalin, isoquercitrin, nicotiflorin, and rutin, as the saponins soyasapogenol B 3-O-${\beta}$-D-glucuronopyranoside, azukisaponins II and V, soyasaponins II and V and as 4-O-${\beta}$-Dglucopyranosyl syringic acid, uracil and n-hexacosanol. Five saponins and 4-O-${\beta}$-D-glucopyranosyl syringic acid were isolated from the BuOH fraction as their methyl esters. Ombuoside (rutin 7,4'-di-O-methyl ether) was also isolated from the methylated BuOH-soluble fraction. However, no ombuoside was detected in the HPLC analysis of the nonmethylated BuOH fraction. Therefore, ombuoside is an artifact derived from methylation of rutin. All of these compounds were isolated for the first time from this plant.

• Journal of Hydrogen and New Energy
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• v.22 no.6
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• pp.895-904
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• 2011

Stratified charge has been thought as one of the ways to avoid a sharp pressure rise on HCCI combustion. The purpose of this study is to evaluate the potential of stratified charge for reducing PRR on HCCI combustion. The pre-mixture with thermal, mixing and EGR stratifications is charged in Rapid Compression Machine. After that, the pre-mixture is compressed and in that process, in-cylinder gas pressure and temperature are analyzed. Additionally numerical calculation with multi-zones modeling is run to know the potential of stratified charge for reducing PRR.