• Biomedical Science Letters
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• v.12 no.3
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• pp.241-247
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• 2006

To evaluate an effect of pathological liver damage on the cyclohexane (CH) metabolism, rats were pretreated with 50% carbon tetrachloride $(CCl_4)$ dissolved in olive oil (0.1ml/100g body weight) 10 or 17 times intraperitoneally at intervals of every other day. To these liver damaged animals, CH (a single dose of 1.56g/kg body weight, i.p.) was administered at 48hr after the last injection of $CCl_4$. The CH metabolites; cyclohexanol (CH-ol), cyclohexane-l,2-diol (CH-l,2-diol) and cyclohexane-l,4-diol (CH-l,4-diol) and cyclohexanone (CH-one) were detected in the urine of CH treated rats. After CH treatment, the serum levels of CH-ol and CH-one were remarkably increased at 4 hr and then decreased at 8hr in normal group. Whereas in liver damaged rats, these CH metabolites were higher at 8hr than at 4hr. The excretion rate of CH metabolites trom serum into urine was more decreased in liver damaged animals than normal group, with the levels of excretion rate being lower in $CCl_4$ 17 times injected animals than 10 times injected ones. It was interesting that the urinary concentration of CH metabolites was generally more increased in liver damaged animals than normal ones, and the increasing rate was higher in $CCl_4$ 17 times injected rats than 10 times injected ones. Taken all together, it is assumed that reduced urinary excretion rate of CH metabolites in liver damaged rats might be resulted from deteriorated hepatic and renal blood flow, and an increased urinary excretion amount of CH metabolites in liver damaged rats might be caused by reduced expiration amount of the metabolites due to lung damage.

• Investigative Magnetic Resonance Imaging
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• v.12 no.1
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• pp.8-19
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• 2008

Purpose : To investigate the 3-bond and spatial connectivity of human brain metabolites by scalar coupling and dipolar nuclear Overhauser effect/enhancement (NOE) interaction through 2D- correlation spectroscopy (COSY) and 2D- NOE spectroscopy (NOESY) techniques. Materials and Methods : All 2D experiments were performed on Bruker Avance 500 (11.8 T) with the zshield gradient triple resonance cryoprobe at 298 K. Human brain metabolites were prepared with 10% $D_2O$. Two-dimensional spectra with 2048 data points contains 320 free induction decay (FID) averaging. Repetition delay was 2 sec. The Top Spin 2.0 software was used for post-processing. Total 7 metabolites such as N-acetyl aspartate (NAA), creatine (Cr), choline (Cho), lutamine (Gln), glutamate (Glu), myo-inositol (Ins), and lactate (Lac) were included for major target metabolites. Results : Symmetrical 2D-COSY and 2D-NOESY pectra were successfully acquired: COSY cross peaks were observed in the only 1.0-4.5 ppm, however, NOESY cross peaks were observed in the 1.0-4.5 ppm and 7.9 ppm. From the result of the 2-D COSY data, cross peaks between the methyl protons ($CH_3$(3)) at 1.33 ppm and methine proton (CH(2)) at 4.11 ppm were observed in Lac. Cross peaks between the methylene protons (CH2(3,$H{\alpha}$)) at 2.50ppm and methylene protons ($CH_2$,(3,$H_B$)) at 2.70 ppm were observed in NAA. Cross peaks between the methine proton (CH(5)) at 3.27 ppm and the methine proton (CH(4,6)) at 3.59 ppm, between the methine proton (CH(1,3)) at 3.53 ppm and methine proton (CH(4,6)) at 3.59 ppm, and between the methine proton (CH(1,3)) at 3.53 ppm and methine proton (CH(2)) at 4.05 ppm were observed in Ins. From the result of 2-D NOESY data, cross peaks between the NH proton at 8.00 ppm and methyl protons ($CH_3$) were observed in NAA. Cross peaks between the methyl protons ($CH_3$(3)) at 1.33 ppm and methine proton (CH(2)) at 4.11 ppm were observed in Lac. Cross peaks between the methyl protons (CH3) at 3.03 ppm and methylene protons (CH2) at 3.93 ppm were observed in Cr. Cross peaks between the methylene protons ($CH_2$(3)) at 2.11 ppm and methylene protons ($CH_2$(4)) at 2.35 ppm, and between the methylene protons($CH_2$ (3)) at 2.11 ppm and methine proton (CH(2)) at 3.76 ppm were observed in Glu. Cross peaks between the methylene protons (CH2 (3)) at 2.14 ppm and methine proton (CH(2)) at 3.79 ppm were observed in Gln. Cross peaks between the methine proton (CH(5)) at 3.27 ppm and the methine proton (CH(4,6)) at 3.59 ppm, and between the methine proton (CH(1,3)) at 3.53 ppm and methine proton (CH(2)) at 4.05 ppm were observed in Ins. Conclusion : The present study demonstrated that in vitro 2D-COSY and NOESY represented the 3-bond and spatial connectivity of human brain metabolites by scalar coupling and dipolar NOE interaction. This study could aid in better understanding the interactions between human brain metabolites in vivo 2DCOSY study.

• Korean Journal of Materials Research
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• v.22 no.7
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• pp.358-361
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• 2012

Co and Ni as catalysts in $SnO_2$ sensors to improve the sensitivity for $CH_4$ gas and $CH_3CH_2CH_3$ gas were coated by a solution reduction method. $SnO_2$ thick films were prepared by a screen-printing method onto $Al_2O_3$ substrates with an electrode. The sensing characteristics were investigated by measuring the electrical resistance of each sensor in a chamber. The structural properties of $SnO_2$ with a rutile structure investigated by XRD showed a (110) dominant $SnO_2$ peak. The particle size of the $SnO_2$:Ni powders with Ni at 6 wt% was about 0.1 ${\mu}m$. The $SnO_2$ particles were found to contain many pores according to a SEM analysis. The sensitivity of $SnO_2$-based sensors was measured for 5 ppm of $CH_4$ gas and $CH_3CH_2CH_3$ gas at room temperature by comparing the resistance in air to that in the target gases. The results showed that the best sensitivity of $SnO_2$:Ni and $SnO_2$:Co sensors for $CH_4$ gas and $CH_3CH_2CH_3$ gas at room temperature was observed in $SnO_2$:Ni sensors coated with 6 wt% Ni. The $SnO_2$:Ni gas sensors showed good selectivity to $CH_4$ gas. The response time and recovery time of the $SnO_2$:Ni gas sensors for the $CH_4$ and $CH_3CH_2CH_3$ gases were 20 seconds and 9 seconds, respectively.

• Bulletin of the Korean Chemical Society
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• v.7 no.6
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• pp.468-471
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• 1986

The isolated products from the reactions of $Rh(ClO_4)(CO)(PPh_3)_2$ (1) with CH_2$ = $CHCO_2C_2H_5$ (2) and trans-$CH_3CH$ = $CHCO_2C_2H_5$ (3) contain 80∼ 90% of $[Rh(CH_2 = CHCO_2C_2H_5)(CO)(PPh_3)_2]ClO_4$ (4) and [Rh(trans-$CH_3CH = CHCO_2C_2H_5(CO)(PPh_3)_2]ClO_4$ (5), respectively where 2 and 3 seem to be coordinated through the carbonyl oxygen. It has been found that complex 1 catalyzes the isomerization of $CH_2 = CH(CH_2)_8CO_2C_2H_5$ (6) to $CH_3(CH_2)_nCH = CH(CH_2)_{7-n}CO_2C_2H_5$ (n = 0∼7) under nitrogen at 25$^{\circ}C$. The isomerization of 6 is slower than that of $CH_2 = CH(CH_2)_9CH_3$ to $CH_3(CH_2)_nCH$ = $CH(CH_2)_{8-n}CH_3$ (n = 0∼8), which is understood in terms of the interactions between the carbonyl oxygen of 6 and the catalyst. It has been also observed that complex 1 catalyzes the hydrogenation of 2, 3, 6, trans-$C_6H_5CH = CHCO_2C_2H_5$ (7), $CH_3(CH_2)_7CH = CH(CH_2)_7CO_2C_2H_5$ (8) and $CH_2 = CH(CH_2)_9CH_3$ (9), and the isomerization (double bond migration) of 6 and 9 under hydrogen at 25$^{\circ}C$. The interactions between the carbonyl oxygen of the unsaturated esters and the catalyst affect the hydrogenation in such a way that the hydrogenation of the unsaturated esters becomes slower than that of simple olefins.

• Journal of the Korean Chemical Society
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• v.41 no.2
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• pp.88-97
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• 1997

The silyltriflates$(Ph_{3-n}SiH(OTf)_n)$have been produced by the reaction of triphenylsilane and triflic acid$(CF_3SO_3H)$at low temperature. These highly reactive compounds are a valuable reagent for the synthesis of numerous new functional substituted silane derivatives. The reaction of silyltriflates with alkenyl- and alkynylmagnesium bromide as well as organolithium compounds gave new silanes$Ph_2SiHR(R=\;C(CPh,\;CH=CH_2,\;CH_2CH=CH_2,\; (CH_2)_2CH=CH_2,\;(CH_2)_3CH=CH_2)$in high yields. The hydrosilation of prepared alkenyl- and alkynylsilanesPh_2SiHR$in the presence of a platinum catalyst(Pt/C) at high temperature$(200{\circ}C)$gave carbosilane polymers$((Ph_2SiCH=CPh)_n$and$(Ph_2Si(CH_2)m)n;\;m=2∼4, n{\ge}10)$along with five- and six-membered silaalkane ring compounds derived from intramolecular hydrosilation reactions. All of the prepared compounds are confirmed by NMR, UV, IR and mass spectroscopy as well as elemental analysis.

• Korean Journal of Materials Research
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• v.21 no.10
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• pp.546-549
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• 2011

Nano-sized $SnO_2$ thick films were prepared by a screen-printing method onto $Al_2O_3$ substrates. The sensing characteristics were investigated by measuring the electrical resistance of each sensor in a test box as a function of the detection gas. The nano-sized $SnO_2$ thick film sensors were treated in a $N_2$ atmosphere. The structural properties of the nano $SnO_2$with a rutile structure according to XRD showed a (110) dominant $SnO_2$ peak. The particle size of $SnO_2$:Ni nano powders at Ni 8 wt% was about 45 nm, and the $SnO_2$ particles were found to contain many pores according to the SEM analysis. The sensitivity of the nano $SnO_2$-based sensors was measured for 5 ppm $CH_4$ gas and $CH_3CH_2CH_3$ gas at room temperature by comparing the resistance in air with that in the target gases. The results showed that the best sensitivity of $SnO_2$:Ni and $SnO_2$:Co sensors for $CH_4$ gas and $CH_3CH_2CH_3$ gas at room temperature was observed in $SnO_2$:Ni sensors doped with 8 wt% Ni. The response time of the $SnO_2$:Ni gas sensors was 10 seconds and recovery time was 15 seconds for the $CH_4$ and $CH_3CH_2CH_3$ gases.

• Bulletin of the Korean Chemical Society
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• v.5 no.5
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• pp.199-201
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• 1984

It has been found that $Rh(ClO_4)(CO)(P(C_6H_5)_3)_2$ catalyzes the hydrogenation and isomerization of soybean oil at room temperature under the atmospheric pressure of hydrogen. The hydrogenation occurs at the olefinic groups to produce saturated groups leaving the ester groups intact, and the isomerization converts $-CH = CH- CH_2-CH = CH-$ units to conjugated dienes and the dienes separated by more than two $-CH_2-$ groups. The rate of the hydrogenation is faster than that of the isomerization.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.3
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• pp.38-42
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• 2000

Plasma polymerized thin films were manufactured inter-electrode coupled plasma polymerization apparatus. The deposition rate reached its maximum between 40[W] and 100[W]. In the ESCA analysis, peaks revealing -CH2, -CH, -C- were present at 285.4 and 285.5[eV] respectively. The C=O peak at 532.8[eV] and the C-O peak at 533.8[eV], which were grouped with an unignorable amount of oxygen were conformed. In ESR analysis, the curve revealing strong amplification was in saturation, which was affected by weak power. This is considered as a -CH-Ch=Ch- structure containing the Allyl group. The relative permittivity of the plasma polymerized thin films was about 3.5 at a frequency of 100[Hz]∼200[kHz]. The dissipation factor showed allow value of 0.008.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.1128-1133
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• 2004

A comprehensive experimental and numerical study has been conducted to understand the influence of $CH_{3}Cl$ addition on $CH_{4}/O_{2}/N_{2}$ premixed flames under the oxygen enrichment. The laminar flame speeds of $CH_{4}/CH_{3}Cl/O_{2}/N_{2}$ premixed flames at room temperature and atmospheric pressure are experimentally measured using Bunsen nozzle flame technique, varying the amount of $CH_{3}Cl$ in the fuel, the equivalence ratio of the unburned mixture, and the level of the oxygen enrichment. The flame speeds predicted by a detailed chemical kinetic mechanism employed are found to be in excellent agreement with those deduced from experiments. As $CH_{3}Cl$ addition is increased temperature at the postflame is not almost varied but the heat release rate and $EI_{NO}$ are decreased. The function of $CH_{3}Cl$ as inhibitor on hydrocarbon flames becomes weakened as the level of the oxygen enrichment is increased from 0.21 to 0.5.

• Journal of Environmental Science International
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• v.20 no.8
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• pp.1011-1019
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• 2011

The objective of this research is to evaluate optimal conditions of permeability and selectivity on the polysulfone membrane for efficiency of separation of $CH_4$ by checking four factors which are temperature, pressure, gas compositions and gas flow rates. When higher pressure was applied at the input, lower efficiency of recovery of $CH_4$ and higher efficiency of separation of $CH_4$ were shown. It has the tendency to show lower efficiency of recovery of $CH_4$ and higher efficiency of separation of $CH_4$ at the output as higher temperature at input. The lower flow rates make higher efficiency of recovery of $CH_4$ and lower efficiency of separation of $CH_4$. Finally, over 90% efficiency for $CH_4$ separation and recovery conditions are temperature ($-5^{\circ}C$), pressure (8 bar), gas composition rate (6:4) ($CH_4:CO_2$) and gas flow rate ($5\ell$/min). These conditions make higher separation and recovery efficiency such as 90.1% and 92.1%, respectively.