• Journal of Satellite, Information and Communications
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• v.10 no.2
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• pp.90-94
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• 2015

We stuidied liauid crystal alignment treatment using solution process for making thin oxide layer in liquid crystal display. It is the one of very effient and popular process in making thin oxide layer in electronical industrial fields. Particularly, this process has highly potential value in liquid crystal display industrial fields because it cause automatically induced alignment process without tranditional alignment process in liquid crystal alignment process. We made several different kinds of mol density solutions using strontium oxide solution. And those solutions were treated for solidification layers using annealing process for 2 hours. And we stuided pretilt angle properties of these alignment layers of strontium oxide for clarifying the relationship of liquid crystal molecules and thin strontium oxide layer. And we also tested the existence of strontium oxide thin layer on substrate using XPS measurement. We expected the hig gain of electro-optical properties in liquid crystal display using strontium oxide thin layer because it has high K property material than the other metal-based oxide layers. In this results, we measured 1.447 to 1.613 thresholds volts as 0.1 mol to 0.4 mol density in 0.1 mol density steps. This is significant better characteristics than conventional liquid crystal display as higher than 1.85 thresholds volts. And it make possible to making next-generation liquid crystal display which present low-power consumption and wide gray scale in liquid crystal display.

• Journal of the Korean Vacuum Society
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• v.1 no.1
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• pp.190-197
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• 1992

In this study we have investigated physical and electrical properties of high temperature oxide (HTO) thin film using dichlorosilane (DCS) gas. This film had low etch rate and excellent step coverage, and its characteristics of Si-O bond were similar to those of thermal oxide. I-V curves also showed similar electrical properties to those of thermally grown oxide (SiO2) while time dependent dielectric breakdown (TDDB) results revealed 1/4 value of thermal oxide. However, defect density was measured to be much lower value than that of thermal oxide.

• BMB Reports
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• v.41 no.8
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• pp.604-608
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• 2008

1-Nitropyrene 4,5-oxide and 1-nitropyrene 9,10-oxide are oxidative metabolites that are responsible for the mutagenicity of 1-nitropyrene. In this study, the mutation spectra induced by oxidative metabolites in human cells were determined using a shuttle vector assay. The mutation frequencies induced by 1-nitropyrene 9,10-oxide were 2-3 times higher than those induced by 1-nitropyrene 4,5-oxide. The base substitutions induced by 1-nitropyrene 4,5-oxide were $G{\rightarrow}A$ transitions, $G{\rightarrow}C$ transversions, and $G{\rightarrow}T$ transversions. In the case of 1-nitropyrene 9,10-oxide, $G{\rightarrow}A$ transitions, $G{\rightarrow}T$ transversions, $A{\rightarrow}G$ transitions and $G{\rightarrow}C$ transversions were observed. Most base substitution mutations induced by oxidative metabolites occurred at the guanine sites in the supF gene. These sequence-specific hot spots were commonly identified as 5'-GA sequences for both metabolites. On the other hand, the sequence-specific hot spots at the adenine sites were identified as 5'-CAC sequences for 1-nitropyrene 9,10-oxide. These results suggest that the oxidative metabolites of 1-nitropyrene induce sequence-specific DNA mutations at the guanine and adenine sites at high frequency.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.10
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• pp.896-901
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• 2005

The microstructure and electrical properties of praseodymium-based zinc oxide varistors were investigated at various cobalt oxide contents in the range of $0.5{\~}5.0 mol\%$. The ceramic density increased in the range of $5.25{\~}5.55 g/cm^3$ with increasing cobalt oxide content. The varistor doped with cobalt oxide of $1.0 mol\%$ exhibited the highest nonlinearity, with 66.6 in nonlinear exponent and 1.2 $\mu$A in leakage current. The donor concentration, density of interface states, and tamer height were in the range of $(1.06{\~}1.69){\times}10^{18}/cm^3$, $(3.11 {\~}3.56){\times}10^{12}/cm^2$, and 0.80${\~}$1.07 eV, respectively.

• Molecules and Cells
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• v.19 no.1
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• pp.114-123
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• 2005

Nitropyrene, the predominant nitropolycyclic hydrocarbon found in diesel exhaust, is a mutagenic and tumorigenic environmental pollutant that requires metabolic activation via nitroreduction and ring oxidation. In order to determine the role of ring oxidation in the mutagenicity of 1-nitropyrene, its oxidative metabolites, 1-nitropyrene 4,5-oxide and 1-nitropyrene 9,10-oxide, were synthesized and their mutation spectra were determined in the coding region of hprt gene of CHO cells by a PCR amplification of reverse-transcribed hprt mRNA, followed by a DNA sequence analysis. A comparison of the two metabolites for mutation frequencies showed that 1-nitropyrene 9,10-oxide was 2-times higher than 1-nitropyrene 4,5-oxide. The mutation spectrum for 1-nitropyrene 4,5-oxide was base substitutions (33/49), one base deletions (11/49) and exon deletions (5/49). In the case of 1-nitropyrene 9,10-oxide, base substitutions (27/50), one base deletions (15/50), and exon deletions (8/50) were observed. Base substitutions were distributed randomly throughout the hprt gene. The majority of the base substitutions in mutant from 1-nitropyrene 4,5-oxide treated cells were $A{\rightarrow}G$ transition (15/33) and $G{\rightarrow}A$ transition (8/33). The predominant base substitution, $A{\rightarrow}G$ transition (11/27) and $G{\rightarrow}A$ transition (8/27), were also observed in mutant from 1-nitropyrene 9,10-oxide treated cells. The mutation at the site of adenine and guanine was consistent with the previous results, where the sites of DNA adduct formed by these compounds were predominant at the sites of purines. A comparison of the mutational patterns between 1-nitropyrene 4,5-oxide and 1-nitropyrene 9,10-oxide showed that there were no significant differences in the overall mutational spectrum. These results indicate that each oxidative metabolite exhibits an equal contribution to the mutagenicity of 1-nitropyrene, and ring oxidation of 1-nitropyrene is an important metabolic pathway to the formation of significant lethal DNA lesions.

• Journal of the Korean institute of surface engineering
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• v.53 no.1
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• pp.36-42
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• 2020

In this study, two novel methods to measure the surface hardness of anodic oxide films on aluminum alloys are reported. The first method is to impregnate oil-based ink into pores in the anodic oxide film and then to clean the ink on the surface using ethanol, resulting in an impregnation of inks only inside of the pores in anodic oxide film. The second method is to coat the anodic oxide film surface with thin Au layer less than 0.1 ?. Both the ink-impregnating method and Au-coating method provided clear indentation marks on the anodic oxide film surface when it was indented using a pyramidal-diamond penetrator. Thus, Vickers hardness of anodic oxide films on aluminium alloy could be measured successfully and precisely from the anodic film surface. In addition, advantages and disadvantages of the ink-impregnating method and Au-coating method for the measurement of surface hardness of anodic oxide films are discussed.

• BMB Reports
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• v.28 no.4
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• pp.301-305
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• 1995

Considering the stimulatory effects of ginsenosides from Panax ginseng C. A. Meyer on the release of nitric oxide from bovine aortic endothelial cells in vitro and vasodilatation of rabbit pulmonary artery in vivo, the present study is designed to investigate the mechanism of nitric oxide release by ginsenosides in calf pulmonary artery endothelial cells, Nitric oxide release was determined in endothelial cells treated with ginsenosides and compared with those of the receptor-dependent agonists, bradykinin and ADP and the receptor-independent calcium ionophore $A_{23187}$. The results showed that total saponin and ginsenoside $Rg_1$, not $Rb_1$, stimulated nitric oxide release measured as conversion to L-citrulline. The nitric oxide releasing properties of total saponin and ginsenoside $Rg_1$ were different; total saponin stimulated only conversion to L-citrulline, like $A_{23187}$, while ginsenoside $Rg_1$ stimulated both L-arginine transport and conversion to L-citrulline, as bradykinin or ADP did.

• Journal of the Korean Ceramic Society
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• v.11 no.1
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• pp.3-9
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• 1974

The role of added metal oxide in the adherence mechanism of low melting glass to several metal plates such as oxygen free high conducting copper, low carbon steel, chrominum galvanized on copper, and stainless steel was investigated. The metal oxide which added to glass were cupric oxide, ferric oxide, chromic oxide, and stainless steel oxide. The glass to that various metla oxide were added, sealed with several metal plates in the electric furnace at $650^{\circ}C$ for 5 minutes. The results as follows; 1) The interfacial reaction was promoted and strong chemical bonding with glass and metals by which the surface energy was decreased showed excellent sealing by addition of metal oxide. 2) When the interfacial reaction of glass and metals was promoted by addition of metal oxide found out that various adhernece mechanism were related to the sealing. 3) When the amount of metal oxide addition was 3-5% the excellent sealing was achieved.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.7
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• pp.792-798
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• 2013

In this study, we have carried out measurement for exhaust emissions such as particulate matter (PM), nitrogen oxide and carbon oxide from main engines installed on the training ships, HANBADA and HANNARA, of Korea Maritime University. In particular, we considered the two conditions; at arrivals/departures and at constant speed of about 160 rpm. The result showed that the concentration of PM at the ship arrival was 2.41mg/m3. On the other hand, when the ship is on the navigation condition, the concentration of PM was 1.34 mg/m3. The concentrations of nitrogen oxide and carbon oxide were measured in the range of 1,120~1,600 ppm and 320~1,450 ppm at the arrival and departure at the port. Under constant speed condition, the concentrations of nitrogen oxide and carbon oxide were 913~1,470 ppm and 73~460 ppm, respectively. Generally, the concentrations of exhaust emissions under the arrivals and departures were higher than that of constant speed condition. These results imply that the ship operation skill to prevent a sudden load change of main engine is needed during the arrival or departure. In addition, it means that the difference of exhaust emissions according to navigation conditions has to be considered when the reduction technologies of air pollutants from ships are developed.

• Journal of Electrochemical Science and Technology
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• v.2 no.1
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• pp.1-7
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• 2011

Nanocomposites of reduced graphene oxide and manganese (II,III) oxide can be synthesized by the freeze-drying process of the mixed colloidal suspension of graphene oxide and manganese oxide, and the subsequent heat-treatment. The calcined reduced graphene oxide-manganese (II,III) oxide nanocomposites are X-ray amorphous, suggesting the formation of homogeneous and disordered mixture without any phase separation. The reduction of graphene oxide to reduced graphene oxide upon the heat-treatment is evidenced by Fourier-transformed infrared spectroscopy. Field emission-scanning electronic microscopy and energy dispersive spectrometry clearly demonstrate the formation of porous structure by the house-of-cards type stacking of reduced graphene oxide nanosheets and the homogeneous distribution of manganese ions in the nanocomposites. According to Mn K-edge X-ray absorption spectroscopy, manganese ions in the calcined nanocomposites are stabilized in octahedral symmetry with mixed Mn oxidation state of Mn(II)/Mn(III). The present reduced graphene oxide-manganese oxide nanocomposites show characteristic pseudocapacitance behavior superior to the pristine manganese oxide, suggesting their applicability as electrode material for supercapacitors.