• The Journal of the Petrological Society of Korea
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• v.25 no.1
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• pp.13-27
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• 2016

The characteristics of the rock cleavage inherent in Jurassic granite from Geochang were analysed. The phases of distribution of microcrack spacings were derived from the enlarged photomicrographs(${\times}6.7$) of the thin section. The evaluation for the six directions of rock cleavages was performed using nine parameters such as (1) frequency of microcrack spacing(N), (2) frequency ratio(${\leq}1mm$ and 4 mm >) to total spacing frequency(N:191), (3) spacing ratio(${\leq}1mm$) to total spacing(118.49 mm), (4) mean spacing($S_{mean}$), (5) difference value($S_{mean}-S_{median}$) between mean spacing and median spacing($S_{median}$), (6) density of spacing, (7) median spacing, (8) reduction ratio of spacing frequency to length frequency and (9) magnitude of exponent(${\lambda}$ and b) related to the distribution type of diagram. Especially the close dependence between the above spacing parameters and the parameters from the spacing-cumulative frequency diagrams was derived. The results of correlation analysis between the values of parameters for three rock cleavages and those for three planes are as follows. The values of (I) parameters(1, 2 and 3), (II) parameters(4, 5 and 6), (III) parameter(7), (IV) parameter(8) and (V) parameter(9) show the various orders of H(hardway, H1+H2) < G(grain, G1+G2) < R(rift, R1+R2), R < G < H, R < H < G, G < H < R and H < G < R, respectively. On the contrary, the values of the above four groups(I~IV) of parameters for three planes show reverse orders. This type of correlation analysis is useful for discriminating three quarrying planes. Six spacing-cumulative frequency diagrams were arranged in increasing order on the value of main parameter($S_{mean}-S_{median}$). These diagrams show an order of R2 < R1 < G2 < G1 < H2 < H1 from the related chart. In other words, the above six diagrams can be summarized in order of rift(R1+R2) < grain(G1+G2) < hardway(H1+H2). These results indicate a relative magnitude of rock cleavage related to microcrack spacing. Especially, the above main parameter could provide advanced information for prediction the order of arrangement among the diagrams.

• Proceedings of the PSK Conference
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• 2001.04a
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• pp.230.2-230.2
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• 2001

• Elastomers and Composites
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• v.53 no.2
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• pp.75-79
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• 2018

ZnS:Mn-glycine (ZnS:Mn-Gly) nanocomposites were synthesized by capping ZnS:Mn nanocomposites with glycine. Zinc sulfate heptahydrate ($ZnSO_4{\cdot}7H_2O$), glycine ($C_2H_5NO_2$), manganese sulfate monohydrate ($MnSO_4{\cdot}H_2O$), and sodium sulfide ($Na_2S$) were used as the source reagents. $ZnS:Mn-Gly-C_{60}$ nanocomposites were obtained by heating the ZnS:Mn-Gly nanocomposites and fullerene ($C_{60}$) at a 2:1 mass ratio in an electric furnace at $700^{\circ}C$ for 2 h. X-ray diffraction (XRD) was used to characterize the crystal structure of the synthesized nanocomposites. The photocatalytic activity of the $ZnS:Mn-Gly-C_{60}$ nanocomposites was evaluated, via the degradation of brilliant green (BG) dye under 254 nm irradiation, with a UV-vis spectrophotometer.

• International Journal of Oral Biology
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• v.31 no.4
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• pp.127-133
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• 2006

[ $H_2O_2$ ], a member of reactive oxygen species (ROS), is known to be involved in the mediation of physiological functions in a variety of cell types. However, little has been known about the physiological role of $H_2O_2$ in exocrine cells. Therefore, in the present study, the effect of $H_2O_2$ on cholecystokinin (CCK)-evoked $Ca^{2+}$ mobilization and amylase release was investigated in rat pancreatic acinar cells. Stimulation of the acinar cells with sulfated octapeptide form of CCK (CCK-8S) induced biphasic increase in amylase release. Addition of $30\;{\mu}M\;H_2O_2$ enhanced amylase release caused by 10 pM CCK-8S, but inhibited the amylase release induced by CCK-8S at concentrations higher than 100 pM. An ROS scavenger, $10\;{\mu}M$ Mn(III)tetrakis(4-benzoic acid)porphyrin chloride, increased amylase release caused by CCK-8S at concentrations higher than 100 pM, although lower concentrations of CCK-8S-induced amylase release was not affected. To examine whether the effect of $H_2O_2$ on CCK-8S-induced amylase release was exerted via modulation of intracellular $Ca^{2+}$ signaling, we measured the changes in intracellular $Ca^{2+}$ concentration $([Ca^{2+}]_i)$ in fura-2 loaded acinar cells. Although $30\;{\mu}M\;H_2O_2$ did not induce any increase in $[Ca^{2+}]_i$ by itself, it increased the frequency and amplitude of $[Ca^{2+}]_i$ oscillations caused by 10 pM CCK-8S. However, $30\;{\mu}M\;H_2O_2$ had little effect on 1 nM CCK-8S-induced increase in $[Ca^{2+}]_i$. ROS scavenger, 1 mM N-acetylcysteine, did not affect $[Ca^{2+}]_i$ changes induced by 10 pM or 1 nM CCK-8S. Therefore, it was concluded that $30\;{\mu}M\;H_2O_2$ enhanced low concentration of CCK-8S-induced amylase release probably by increasing $[Ca^{2+}]_i$ oscillations while it inhibited high concentration of CCK-8S-induced amylase release.

• Journal of the Korean institute of surface engineering
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• v.52 no.3
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• pp.111-116
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• 2019

Chromium was coated on a steel substrate by the Cr(III) electroplating method, and corroded at $500-900^{\circ}C$ for 5 h in $N_2/0.1%H_2S-mixed$ gas to study the high-temperature corrosion behavior of the Cr(III) coating in the highly corrosive $H_2S-environment$. The coating consisted of (C, O)-supersaturated, nodular chromium grains with microcracks. Corrosion was dominated by oxidation owing to thermodynamic stability of oxides compared to sulfides and nitrides. Corrosion initially led to formation of the thin $Cr_2O_3$ layer, below which (S, O)-dissolved, thin, porous region developed. As corrosion progressed, a $Fe_2Cr_2O_4$ layer formed below the $Cr_2O_3$ layer. The coating displayed relatively good corrosion resistance due to formation of the $Cr_2O_3$ scale and progressive sealing of microcracks.

• Korean Journal of Food Science and Technology
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• v.43 no.6
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• pp.791-794
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• 2011

The aim of this study was to investigate the antimicrobial characteristics of citral against Salmonella Typhimurium and Staphylococcus aureus. Antimicrobial activities were determined according to the citral concentration and initial pH. The tested citral concentrations were 0-1,000 ppm in tryptic soy broth (TSB) and 0-5,000 ppm in Angelica keiskei juice (NokJeup). The initial pHs tested were 4-7. Antimicrobial activities increased as citral concentration increased. S. aureus was more susceptible than S. Typhimurium during culture in TSB. But S. aureus was less susceptible to pH changes. Citral caused about 1-2 log reduction of S. aureus and 2-5 log reduction of S. Typhimurium after 10 min exposure at different pHs. As the citral concentration in the Algelica keiskei juice increased, S. aureus was easily inactivated but S. Typhimurium was not inactivated.

• Journal of Wetlands Research
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• v.23 no.1
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• pp.54-59
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• 2021

DIWS system was introduced to remove hydrogen sulfide from the biogas of wastewater treatment plant. In the case of using water into the DIWS system more than 5,000mg/L of hydrogen sulfide, 25% of H2S removal efficiency was shown and required such further treatment process as incineration which was obtained more than 98%. When the inflow of hydrogen sulfide was 5,000mg/L, CH4 and CO2 were effectively discharged and the reduction was 8.7% and 28.6%, respectively. When such neutralization chemicals as Na2CO3 and NaOH were introduced into the DIWS system, H2S was removed more than 97.2% keeping pH in the range of 11.2 to 11.5.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.12
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• pp.1347-1352
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• 2005

[ $H_2S$ ] removal reaction using $Li_2ZrO_3/honeycomb$ has been carried out in a fixed bed reactor for the cleaning of syngas from the waste gasifier. $Li_2ZrO_3$ was synthesised using reagent-grade $Li_3CO_3$ and $ZrO_2$ with suitable amount of ethanol in a 1:1 ratio. And then $Li_2ZrO_3$ were calcined in air at $850{\sim}1000^{\circ}C$ for 14 h. The optimum condition of $H_2S$ removal reaction is around 20 wt% $Li_2ZrO_3$/honeycomb at 300 mL/min and $700^{\circ}C$. At this condition, removal amount of $H_2S$ was about 0.337 $g^{H_2S}/g^{sorbent}$. Addition of $K_2CO_3$, $Na_2CO_3$, NaCl and LiCl in the $Li_2ZrO_3$ remarkably improves the $H_2S$ removal capacity of modified $Li_2ZrO_3$/honeycomb up to 23%. Analyses of $Li_2ZrO_3/honeycomb$ sorbent by SEM and XRD showed that $Li_2ZrO_3$ was uniformly impregnated into honeycomb up to considerable amounts. Furthermore, the physicochemical properties of the sorbent did not vary much up to $1000^{\circ}C$.

• Bulletin of the Korean Chemical Society
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• v.21 no.3
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• pp.291-294
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• 2000

The bulk photopolymerization of methyl methacrylate(MMA) with bis(silane)s such as 1,4-$C_6H_4(SiH_3)_2$ (1) and 1,4-$C_6H_4(SiH_2Me)_2$ (2) was performed to produce poly(MMA)s possessing the corresponding bis(silyl) moiety as an end group. For the bis(silane)s, while the polymerizaiton yields and the polymer molecular weights decreased, the TGA residue yields and the relative intensities of Si-H IR stretching bands increased as the relative bis(silane) concentration over MMA increased. The polymerizaion yield, polymer molecular weight, and TGA residue yield of MMA with 1 were found to be higher than those with 2. The bis(silane)s appears to influence significantly upon the photopolymerization of MMA as both chain initiation and chain transfer agents.

• The Korean Journal of Zoology
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• v.19 no.3
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• pp.113-122
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• 1976

The rate of $^{3}H$-thymidine uptake induced by MMS in asynchronous HeLa $S_3$ suspension cells was decreased in direct proprotion to dose increase. The combined treatment of BUdR or IUdR with MMS was more effective in reducing the rate of $^{3}H$-thymidine uptake. MMS-stimulated $^{3}H$-thymidine uptake was detected in synchronized $G_2$ stage cells of HeLa $S_3$ suspension cultures following treatment with thymidine double shock. BUdR and IUdR greatly enhanced MMS-stimulated $^{3}H$-thymidine uptake. IUdR was found to be a more effective sensitizer than BUdR in this respect.