• Journal of the Korean Vacuum Society
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• v.7 no.3
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• pp.242-247
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• 1998

Hydrogenated amorphous carbon nitride[a-C:H(N)] films were deposited on p-type Si(100) at room temperature with bias voltage of 200 V by DC saddle-field plasma-enhanced chemical vapor deposition. Effects of the ratio of $N_2$ to $CH_4$($N_2/CH_4$), in the range of 0 and 4 on such properties as optical properties, microstucture, relative fraction of nitrogen and carbon, etc. of the films have been investigated. The thickness of the a-C:H(N) film was abruptly decreased with the addition of nitrogen, but at $N_2/CH_4$>0.5, the thickness of the film gradually decreased with the increase of the $N_2/CH_4$. The ratio of N to C(N/C) of the films was saturated at 0.25 with the increase of $N_2CH_4$. N-H, C≡N bonds of the films increased but C-H bond decreased with the increase of $N_2CH_4$.Optical band gap energy of the film decreased from 2.53 eV at the ratio of $N_2CH_4$=4.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.4
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• pp.288-292
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• 1998

In this paper, we fabricated $SnO_2$ composite ceramics doped with 0~20mol% $SnO_2$ of bulk type to investigate the CO and $H_2$ gas sensitivity in various composition, temperature, and concentration of CO and $H_2$ gas. At the temperature range from $100^{\circ}C\sim425^{\circ}C$, the measured 1000ppm and 250ppm CO gas sensitivities of $SiO_2-SnO_2$composite ceramics were about 1.0~7.6 and 1.0~5.6, respectively. These values were about 1.0~1.5 times larger than pure $SnO_2$. The maximum 1000ppm CO gas sensitivity of $SiO_2-SnO_2$composites were measured around $325^{\circ}C$. At the temperature range from $270^{\circ}C\sim380^{\circ}C$, the 1000ppm and 500ppm $H_2$gas sensitivities of $SiO_2-SnO_2$ composites were about 2.9~21.2 and 2.1~11.3, respectively. Also the maximum 1000, 500 ppm $H_2$ gas sensitivities of samples were measured around.

• Journal of the Korean Chemical Society
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• v.57 no.4
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• pp.447-454
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• 2013

In this research, two new complexes of N-(2-aminoethyl)-1,3-propanediamine (aepn), $[Cd(aepn)_2]I_2$ (1) and $[Cd(aepn)_2]Cl_2{\cdots}H_2O$ (2), were prepared and identified by elemental analysis, FT-IR, Raman spectroscopy and single-crystal X-ray diffraction. Geometry around the cadmium atom in two complexes by coordination of six nitrogen atoms of two aepn is distorted octahedral. If distortion in the mer-$[Cd(aepn)_2]^{2+}$ cation is disregarded, it has a $C_2$ axis and $C_2$ symmetry. The cyclic voltammetry experiments were carried out to study the complexation process. Two structural surveys on coordination modes and complexes of aepn are presented. A study was carried out using CSD data to estimate the averages of bond lengths for different types of the Cd-N bonds. It was found that the intermolecular $N-H{\cdots}I$, $C-H{\cdots}I$ hydrogen bonds in 1 and $N-H{\cdots}Cl$, $N-H{\cdots}O$, $C-H{\cdots}O$, $O-H{\cdots}Cl$ in 2 stabilized the crystal networks.

• Journal of The Korean Dental Society of Anesthesiology
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• v.14 no.1
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• pp.49-56
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• 2014

Background: Propofol (2.6-diisopropylphenol) is a widely used intravenous anesthetic agent for the induction and maintenance of anesthesia during surgeries and sedation for ICU patients. Propofol has a structural similarity to the endogenous antioxidant vitamin E and exhibits antioxidant activities.13) However, the mechanism of propofol on hypoxia/reoxygenation (H/R) injury has yet to be fully elucidated. We investigated how P-PostC influences the autophagy and cell death, a cellular damage occurring during the H/R injury. Methods: The groups were randomly divided into the following groups: Control: cells were incubated in normoxia (5% CO2, 21% O2, and 74% N2) without propofol treatment. H/R: cells were exposed to 24 h of hypoxia (5% CO2, 1% O2, and 94% N2) followed by 12 h of reoxygenation (5% CO2, 21% O2, and 74% N2). H/R + P-PostC: cells post-treated with propofol were exposed to 24 h of hypoxia followed by 12 h of reoxygenation. 3-MA + P-PostC: cells pretreated with 3-MA and post-treated propofol were exposed to 24 h of hypoxia followed by 12 h of reoxygenation Results: The results of our present study provides a new direction of research on mechanisms of propofol-mediated cytoprotection. There are three principal findings of these studies. First, the application of P-PostC at the onset of reoxygenation after hypoxia significantly increased COS-7 cell viability. Second, the cellular protective effect of P-PostC in H/R induced COS-7 cells was probably related to activation of intra-cellular autophagy. And third, the autophagy pathway inhibitor 3-MA blocked the protective effect of P-PostC on cell viability, suggesting a key role of autophagy in cellular protective effect of P-PostC. Conclusions: These data provided evidence that P-PostC reduced cell death in H/R model of COS-7 cells, which was in agreement with the protection by P-PostC demonstrated in isolated COS-7 cells exposed to H/R injury. Although the this study could not represent the protection by P-PostC in vivo, the data demonstrate another model in which endogenous mechanisms evoked by P-PostC protected the COS-7 cells exposed to H/R injury from cell death.

• Journal of Food Hygiene and Safety
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• v.12 no.3
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• pp.200-204
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• 1997

Effects of benzoate (0~0.6 g/$\ell$ ) and sorbate (0~2.0 g/$\ell$) on the growth of Escherichia coli O157:H7 in tryptic soy broth at various pH levels (4~8) and temperatures (4$^{\circ}C$, 37$^{\circ}C$) were investigated. Benzoate and sorbate were inhibited the growth of E. coli O157:H7 up to 12 hours cultivation at 4$^{\circ}C$, and 2.0 g/$\ell$ sorbate was only inhibited during 48 hours cultivation at 37$^{\circ}C$. Among the pH levels tested, pH 4 showed significant inhibitory effect against the E. coli O157:H7 on 4$^{\circ}C$ and at 37$^{\circ}C$, respectively. When used in combination 0.2 g/$\ell$ benzoate and sorbate were completely inhibited the growth of E. coli O157:H7 on pH 4 and at 37$^{\circ}C$. While on pH 5 at 4$^{\circ}C$, all of the concentration tested did not exert any inhibitory effect. The combined effects were retarded more than single treatment of E. coli O157:H7.

• Journal of Hydrogen and New Energy
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• v.19 no.1
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• pp.41-48
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• 2008

Fermentative $H_2$ production was studied using microbial consortia isolated from heat-treated ($90{\circ}C$, 20 min) sewage sludge. Important parameters investigated were carbon(C) and nitrogen(N)-sources, C/N ratio, phosphate concentration, pH and temperature during anaerobic cultivation in serum bottles. Starch, ribose, sucrose and glucose were good C-sources for the culture growth and $H_2$ production. Yeast extract was better N-source than $(NH_4)_2SO_4$ or peptone when individually added to the synthetic media, however the combination of above three N-sources exhibited the additional effect for cell growth and $H_2$ evolution. Addition of 100 mM phosphate as a buffering agent prevented the rapid pH drop during the cultivation. The optimum initial pH for the cell growth was at 7.0, whereas $H_2$ production was observed at pH 5.5. Optimum temperature for the cell growth and $H_2$ production was $37{\circ}C$. Initial C/N ratio of 1.22 in the media using glucose and yeast extract as the C- and N-sources, respectively, showed the $H_2$ yield 1.0 mol $H_2$/mol glucose.

• Journal of the Korean Magnetic Resonance Society
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• v.23 no.2
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• pp.40-45
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• 2019

The phase transition temperatures and thermodynamic properties of $(NH_4)_2MnCl_4{\cdot}2H_2O$ grown by the slow evaporation method were studied using differential scanning calorimetry and thermogravimetric analysis. A structural phase transition occurred at temperature $T_{C1}$ (=264 K), whereas the changes at $T_{C2}$ (=460 K) and $T_{C3}$ (=475 K) seemed to be chemical changes caused by thermal decomposition. In addition, the chemical shift and the spin-lattice relaxation time $T_{1{\rho}}$ were investigated using $^1H$ magic-angle spinning nuclear magnetic resonance (MAS NMR), in order to understand the role of $NH_4{^+}$ and $H_2O$. The rise in $T_{1{\rho}}$ with temperature was related to variations in the symmetry of the surrounding $H_2O$ and $NH_4{^+}$.

• Microbiology and Biotechnology Letters
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• v.1 no.1
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• pp.51-57
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• 1973

2,2'-Methylene bis (3,4,6-trichloroacetoxy benzene) had been synthesized from Hexachlorophene. The eleven new derivatives -(2,2'Methylene bis [3,4,6-trichloro o-(${\beta}$-anilinopropionoxy) benzene]: m. p 173∼4$^{\circ}C$, C$\_$31/H$\_$24/N$_2$O$_4$Cl$\_$6/, 2,2' Methylene bis [3,4,6-trichloro (${\beta}$-Cyclohexylaminopropionoxy) benzene]: M. P, 187∼8$^{\circ}C$, C$\_$31/H$\_$36/N$_2$O$_4$Cl$\_$6/, 2,2'-Methylene bis [3,4,6-trichloro (${\beta}$-phenyl hydrazinopropionoxy) benzene]; M. P. 151∼3$^{\circ}C$, C$\_$33/H$\_$28/N$_2$O$_4$Cl$\_$6/, 2,2'-Methylene bis [3,4,6-trichloro (${\beta}$-o-toluidinopropionoxy) benzene]: M. P. 172∼3$^{\circ}C$, C$\_$33/H$\_$28/N$_2$O$_4$Cl$\_$6/, 2,2'-Methylene bis [3,4,6-trichloro (${\beta}$-p-todudinopropionoxy) benzene]: 153∼4$^{\circ}C$, C$\_$33/H$\_$28/N$_2$O$_4$Cl$\_$6/, 2,2'-Methylene bis [3,4,6-trichloro (${\beta}$-o-chloro anilinopropionoxy) benzene]: 170∼2$^{\circ}C$, C$\_$31/H$\_$27/N$_2$O$_4$Cl$\_$8/, 2,2'-Methylene bis [3,4,6-trichloro (${\beta}$-p-sulfamilinopropionoxy) bengene]: M. P. 310-5$^{\circ}C$, C$\_$31/H$\_$24/N$_2$S$_2$O$\_$10/Cl$\_$8/, 2,2'-Methylene bis [3,4,6-trichloro (${\beta}$-piperidinopropionoxy) benzene]: M. P. 168∼2$^{\circ}C$, C$\_$29/H$\_$32/N$_2$O$_4$Cl$\_$6/, 2,2'-Methylene bis (3,4,6-trichloro (${\beta}$-morpholinopropionoxy) benzene]: M. P. 226∼8$^{\circ}C$, C$\_$27/H$\_$28/N$_2$O$\_$6/Cl$\_$6/, 2,2'-Methylene bis (3,4,6-trichloro (${\beta}$-2-amino pyridino propionoxy) benzene]; M. P. 145∼6$^{\circ}C$, C$\_$29/H$\_$22/N$_4$O$_4$Cl$\_$5/-were synthesized by Mannichs reaction as potential antimicrobial agents and their antimicrobial activity were tested against Bacillus subtilis, Pseudomonas ovalis, Escherichia coli, Staphylococcus aureus, aerogenes, Bacillus Acerobacter Polymyxa, Bacillus brevis, Streptomyces griseus, Candida troficalis, Rhodotorula glutinis, Candida utilis, Hansenula anamola, Saccharomyces cerevisiae in vitro. Among them, compounds of benzylamine and p-toludine showed an effective antimibrobial activity againt Bacillus subtilis and Pseudomonas ovalis.

• Korean Journal of Chemical Engineering
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• v.35 no.11
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• pp.2172-2184
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• 2018

The production of isophthalic acid (IPA) from the oxidation of m-xylene (MX) by air is catalyzed by $H_3PW_{12}O_{40}$ (HPW) loaded on carbon and cobalt. We used $H_2O_2$ solution to oxidize the carbon to improve the catalytic activity of HPW@C catalyst. Experiments reveal that the best carbon sample is obtained by calcining the carbon at $700^{\circ}C$ for 4 h after being impregnated in the 3.75% $H_2O_2$ solution at $40^{\circ}C$ for 7 h. The surface characterization displays that the $H_2O_2$ modification leads to an increase in the acidic groups and a reduction in the basic groups on the carbon surface. The catalytic capability of the HPW@C catalyst depends on its surface chemical characteristics and physical property. The acidic groups play a more important part than the physical property. The MX conversion after 180 min reaction acquired by the HPW@C catalysts prepared from the activated carbon modified in the best condition is 3.81% over that obtained by the HPW@C catalysts prepared from the original carbon. The IPA produced by the former is 46.2% over that produced by the latter.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.4
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• pp.142-149
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• 2012

The reduction characteristics of $NO_2$ to NO are experimentally studied over a platinum-based catalyst, especially at lower temperatures below about $200^{\circ}C$. In the present work, two types of steady-state experiments, engine bench and synthetic gas bench tests, are carried out in sequence. Steady-state engine bench tests with the DOC mounted on a light duty 4-cylinder 2.0 liter turbocharged diesel engine are performed and prove that CO plays a major role in $NO_2$ abatement at temperatures below the light-off temperature of CO oxidation, about $200^{\circ}C$. Synthetic gas bench tests are then performed using synthetic gas mixtures with CO, $C_3H_6$, NO, $NO_2$, $O_2$, $H_2O$ and $N_2$ in the $140{\sim}450^{\circ}C$ T-range and show that both CO and $C_3H_6$ are capable of reducing $NO_2$. It is noted that the reaction rate of $NO_2$ with $C_3H_6$ is much higher than that with CO. At temperatures below about $200^{\circ}C$, the reduction of $NO_2$ to NO is promoted with increasing CO concentration and $NO_2$/$NO_X$ ratio and with decreasing $O_2$ concentration, as well as with the presence of $H_2O$.