• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1192-1192
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• 2001

Usually there are many furnaces in a ethylene plant and the performance of total furnaces can be improved if that of each furnace is monitored and controlled. For this purpose real-time data for the effluent of each furnace is necessary. However, it is very difficult to analyze the total effluent stream of a ethylene furnace by real-time because it is composed of so many components including heavy hydrocarbons. Fortunately, component data for lighter hydrocarbons is much more important than that of heavier ones for ethylene furnace. In ordinary case, the on-line measurement of light hydrocarbons is performed by on-stream gas chromatography, after separating gas-phase part from effluent. The main and important components of gas-phase are Methane, Ethane, Ethylene, and Propylene. If we can use Near-infrared spectroscopy for measuring those components within good reproducibility, shorter analysis time, better repeatability, easier maintenance and lower cost will make Near-infrared (NIR) analyzer replace on-stream gas chromatography in this process. Although it is known to be very difficult to measure gas components because of very weak absorption in Near-infrared region, we have studied the feasibility of the application of NIR for the measurement of gas-phase hydrocarbon in the effluent of ethylene furnace. The samples were obtained from actual process and NIR spectra were collected over 1100 to 2500nm range. NIR spectra and calibrations showed and demonstrated the possibility of extending NIR spectroscopy to the measurement of gas-phase hydrocarbon in the effluent of ethylene furnace.

• YAKHAK HOEJI
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• v.40 no.2
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• pp.218-224
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• 1996

This laboratory has recently reported the synthesis and in vitro antitumor activity of PT(II) complexes containing ethylenediamine and diphosphine. In view of the reports of others, cisplatin is toxic to the kidney since the kidney's vulnerability to PT(II) complexes may originate in its ability to accumulate and retain platinum to a greater degree than other organs. The in vitro cytotoxicity of these synthetic PT(II) complexes on the primary cultured proximal tubular cells of rabbit kidney and renal cortical cells of human kidney was investigated. Three endpoints for cytotoxicity tests were evaluated:3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT), $^3H$-thymidine uptake and the glucose consumption tests. The rank order of sensitivity exhibited $^3H$-thymidine uptake>MTT>glucose consumption test. The agents with diphosphine leaving group were significantly less cytotoxic than cisplatin. Moreover, 1,2-bis(diphenylphosphino)ethane (DPPE) exhibited less cytotoxicity than 1.3-bis (diphenylphosphino)propane (DPPP) against on rabbit and human cultured kidney cells. Based on these results, the decreased nephrotoxicity of these new complexes over cisplatin appeared to be partially attributable to a leaving group of DPPP and DPPE. This novel class of platinum compound represents a valuable lead in the development of a "third-generation" agent.

• Journal of Korean Neurosurgical Society
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• v.38 no.5
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• pp.375-379
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• 2005

Objective : Papaverine has been used in treating vasospasm following subarachnoid hemorrhage[SAH]. However, its action mechanism for cerebral vascular relaxation is not clear. Potassium channels are closely related to the contraction and relaxation of cerebral smooth muscle. Therefore, to identify the role of potassium and calcium channels in papaverine-induced vascular relaxation, we examine the effect of papaverine on potassium channels in freshly isolated smooth muscle cells from rat basilar artery. Methods : The isolation of rat basilar smooth muscle cells was performed by special techniques. The whole cell currents were recorded by whole cell patch clamp technique in freshly isolated smooth muscle cells from rat basilar artery. Papaverine was added to the bath solution. Results : Papaverine of $100{\mu}M$ into bath solution increased the amplitude of the outward $K^+$ current which was completely blocked by BKCa[large conductance calcium dependent potassium channels]blocker, IBX[iberiotoxin], and calcium chealator, BAPTA[l,2-bis[o-aminophenoxy]ethane-N,N,N',N'-tetraacetic acid], in whole cell mode. Conclusion : These results strongly suggest that potassium channels may play roles in papaverine-induced vascular relaxation in rat basilar artery.

• Journal of the Korean Applied Science and Technology
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• v.17 no.1
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• pp.1-5
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• 2000

The selective catalytic reduction(SCR) of nitric oxide by ethane in the presence of oxygen was investigated on Cu-ZSM-5, Co-ZSM-5 and Ga-ZSM-5 catalysts over a range of 400, 450 and $500^{\circ}C$. The catalysts were prepared by ion-exchange method. The composition of the reactant gases were 1000 ppm of NO, 1000 ppm of $C_{2}H_{6}$ and 2.5% of $O_{2}$, and the reaction was conducted in a fixed-bed reactor at 1 atm. For the 20wt% Co-ZSM-5(50) catalyst, the NO conversion reached up to 100%, while the $C_2H_6$ conversion and the CO selectivity were about 50% and 25%, respectively, at $450^{\circ}C$. For the 20wt% Cu-ZSM-5(50) catalyst, the NO conversion and the C2H6 conversion were about 80% and 100%, respectively, but there was no CO produced. The metal ion-exchanged ZSM-5 catalysts exhibited a tendency to increase the NO conversion with the Si/Al ratio of the ZSM-5, that is, NO conversion was inversely proportional to the acidity of the catalysts. But, the effect of the acidity on NO conversion was not so large. From the XRD results of the catalysts before and after SCR reaction it was found that there was no structural change.

• Korean Journal of Materials Research
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• v.20 no.9
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• pp.463-466
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• 2010

We studied the initial reaction mechanism of Zn precursors, namely, di-methylzinc ($Zn(CH_3)_2$, DMZ) and diethylzinc ($Zn(C_2H_5)_2$, DEZ), for zinc oxide thin-film growth on a Si (001) surface using density functional theory. We calculated the migration and reaction energy barriers for DMZ and DEZ on a fully hydroxylized Si (001) surface. The Zn atom of DMZ or DEZ was adsorbed on an O atom of a hydroxyl (-OH) due to the lone pair electrons of the O atom on the Si (001) surface. The adsorbed DMZ or DEZ migrated to all available surface sites, and rotated on the O atom with low energy barriers in the range of 0.00-0.13 eV. We considered the DMZ or DEZ reaction at all available surface sites. The rotated and migrated DMZs reacted with the nearest -OH to produce a uni-methylzinc ($-ZnCH_3$, UMZ) group and methane ($CH_4$) with energy barriers in the range of 0.53-0.78 eV. In the case of the DEZs, smaller energy barriers in the range of 0.21-0.35 eV were needed for its reaction to produce a uni-ethylzinc ($-ZnC_2H_5$, UEZ) group and ethane ($C_2H_6$). Therefore, DEZ is preferred to DMZ due to its lower energy barrier for the surface reaction.

• Bulletin of the Korean Chemical Society
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• v.35 no.6
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• pp.1777-1783
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• 2014

Four $Cd^{II}$ MOFs, $[Cd_2({\mu}-succinate)_2(H_2O)_2]{\cdot}H_2O$ (1A), $[Cd_2({\mu}-succinate)_2({\mu}-4,4^{\prime}-bpy)_2]{\cdot}H_2O$ (1B), $[\{Cd_2({\mu}-succinate)_2\}({\mu}-bpa)_2\{Cd(H_2O)_2\}(NO_3)_2]{\cdot}H_2O$ (2), and $[Cd({\mu}-succinate)({\mu}-bpp)_2]{\cdot}2H_2O$ (3), with various bipyridyl ligands (4,4'-bipyridine (4,4'-bpy), 1,2-bis(4-pyridyl)ethane (bpa), and 1,3-bis(4-pyridyl)propane (bpp)) were prepared, and their structures were determined using X-ray crystallography. The structures and dimensionalities of $Cd^{II}$-(succinate) compounds varied depending on the auxiliary ligands. Heterogeneous catalytic activity for transesterification reactions, photoluminescence and the thermal stabilities of these compounds were also examined.

• Transactions of the Korean hydrogen and new energy society
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• v.23 no.6
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• pp.660-669
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• 2012

Gas resources captured in the form of gas hydrates are an order of magnitude larger than the resources available from conventional resources. Focus of this research is to investigate the effect of DME on phase equilibria of methane hydrate, as well as the possibility of the use of the PRO/II computer simulation to estimate the phase equilibria. In systems containing water and a gaseous component like, for instance, methane, ethane, and propane, gas hydrates may occur, if conditions in terms of pressure and temperature are satisfied. Mixtures of gases, e.g. LPG or natural gas, are also able to form gas hydrates in the presence of water. The experiments presented here were performed at temperatures varying between 268.15K and 288.15K and at pressures varying between 1.88 MPa and 10.56 MPa. It was found that the phase equilibria of methane hydrate is influenced by the addition of DME to the system. The pressure for the equilibrium hydrate-liquid water-vapor (H - $L_w$ - V) in the system water + methane is reduced upon addition of DME. The phase equilibria of methane hydrate can be estimated by the PRO/II computer simulation, whereas those of methane hydrate containing DME or LPG can't be estimated properly.

• Applied Chemistry for Engineering
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• v.24 no.4
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• pp.375-381
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• 2013

Kinetics data were obtained for steam reforming of methane and natural gas over the commercial nickel catalyst. Variables for the steam reforming were the reaction temperature and partial pressure of reactants. Parameters for the Power law rate model and the Langmuir-Hinshelwood model were obtained from the kinetic data. As a result of the reforming reaction using pure methane as a reactant, the reaction rate could be determined by the Power law rate model as well as the Langmuir-Hinshelwood model. In the case of methane in natural gas, however, the Langmuir-Hinshelwood model is much more suitable than the Power law rate model in terms of explaining methane reforming reaction. This behavior can be attributed to the competitive adsorption of methane, ethane, propane and butane in natural gas over the same catalyst sites.

• Journal of the Korean Chemical Society
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• v.43 no.2
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• pp.150-155
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• 1999

The ignition delay times behind reflected shock waves in $C_2H_6-O_2-Ar$ systems containing $CH_3Cl$ were measured for the range of temperatures between 1270 and 1544 K. The measurements indicated that $CH_3Cl$ inhibited the ignition of ethane ignition and the inhibition effects increased with increasing $CH_3Cl$ concentration. To clarify the inhibition effects of $CH_3Cl$ from the viewpoint of the reaction mechanism, computational analyses were performed in $C_2H_6-CH_3CI-O_2-Ar$ mixtures.

• Journal of Environmental Health Sciences
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• v.36 no.4
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• pp.323-336
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• 2010

We evaluated the properties of a fixed-bed column reactor for high-concentration tetrachloroethylene (PCE) removal. The anaerobic bacterium Clostridium bifermentans DPH-1 was able to dechlorinate PCE to cis-1,2-dichloroethylene (cDCE) via trichloroethylene (TCE) at high rates in the monoculture biofilm of an upflow fixed-bed column reactor. The first-order reaction rate of C. bifermentans DPH-1 was relatively high at $0.006\;mg\;protein^{-1}{\cdot}l{\cdot}h^{-1}$, and comparable to rates obtained by others. When we gradually raised the influent PCE concentration from $30\;{\mu}M$ to $905\;{\mu}M$, the degree of PCE dechlorination rose to over 99% during the operation period of 2,000 h. In order to maintain efficiency of transformation of PCE in this reactor system, more than 6 h hydraulic retention time (HRT) is required. The maximum volumetric dechlorination rate of PCE was determined to be $1,100\;{\mu}mol{\cdot}d^{-1}l$ of reactor $volume^{-1}$, which is relatively high compared to rates reported previously. The results of this study indicate that the PCE removal performance of this fixed-bed reactor immobilized mono-culture is comparable to that of a fixed-bed reactor mixture culture system. Furthermore, our system has the major advantage of a rapid (5 days) start-up time for the reactor. The flow characteristics of this reactor are intermediate between those of the plug-flow and complete-mix systems. Biotransformation of PCE into innocuous compounds is desirable; however, unfortunately cDCE, which is itself toxic, was the main product of PCE dechlorination in this reactor system. In order to establish a system for complete detoxification of PCE, co-immobilization of C. bifermentans DPH-1 with other bacteria that degrade cDCE aerobically or anaerobically to ethene or ethane may be effective.