• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.1270-1273
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• 2004

The combination of methane-chemical activation and Self-propagating High-temperature synthesis (SHS) has widened the possibilities for both methods. For YBCO systems the investigation showed that a short-term mechano-chemical activation of initial powders before SHS leads to single-phase and ultra-fine products. A new technique for preparation ultra-fine high-temperature superconductors of YBCO composition with a grain size d < $1{\mu}m$ is developed. The specific feature of the technique is formation of the $YBa_2Cu_3O_{7-x}$ crystalline lattice directly from an X-ray amorphous state arising as a result of mechanical activation of the original oxide mixture. The technique allows the stage of formation of any intermediate reaction products to be ruled out. X-ray and magnetic studies of ultra-fine high temperature superconductors (HTS) are carried out. Dimension effects associated with the microstructure peculiarities are revealed. A considerable enhancement of inter-grain critical currents is found to take place in the ultra-fine samples investigated.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05a
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• pp.96-99
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• 2004

The combination of mechano-chemical activation and Self-propagating High-temperature Synthesis (SHS) has widened the possibilities for both methods. For YBCO systems the investigation showed that a short-term mechano-chemical activation of initial powders before SHS leads to single-phase and ultra-fine products. A new technique for preparation ultra-fine high-temperature superconductors of YBCO composition with a grain size d ＜1 ${\mu}{\textrm}{m}$ is developed. The specific feature of the technique is formation of the YBa$_2$Cu$_3$O$_{7-{\delta}}$ crystalline lattice directly from an X-ray amorphous state arising as a result of mechanical activation of the original oxide mixture. The technique allows the stage of formation of any intermediate reaction products to be ruled out. X-ray and magnetic studies of ultra-fine high temperature superconductors (HTS) are carried out. Dimension effects associated with the microstructure peculiarities are revealed. A considerable enhancement of inter-grain critical currents is found to take place in the ultra-fine samples.fine samples.

• Natural Product Sciences
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• v.26 no.2
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• pp.109-117
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• 2020

The canonical Wnt/β-catenin signaling pathways play an important role in the embryonic development, cell proliferation, differentiation, and adhesion. Therefore, the abnormal activation and repression have been associated with uncontrolled homeostasis in human tissues. In particular, the activation of Wnt signaling is highly correlated with a diverse of diseases including cancer. On this regard, a strategy for targeting Wnt/β-catenin signaling has been employed in the discovery and development of antitumor agents. Herein, the evolution of Wnt signaling and the Wnt inhibitors derived from natural products were briefly summarized in the drug discovery of anticancer agents.

• Proceedings of the PSK Conference
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• 2001.10a
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• pp.225.1-225.1
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• 2001

• Journal of Environmental Science International
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• v.24 no.12
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• pp.1601-1608
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• 2015

This study evaluates heavy metal(Cu and Cr) adsorption characteristics produced from food waste charcoal extracted in an optimal operation condition after analyzing activated charcoal of iodine adsorption and heavy metals that derived from an activation process of carbide by the developed by-products of food waste treatment facility using the methods from previous studies. As experiment apparatus, this study used a tube-shaped high temp furnace. The mixing ratio of by-products of food waste treatment facility, carbide, and activation component($ZnCl_2$) was 1:1. The experiment was proceeded as adjusting the activation temperature from 400 to $800^{\circ}C$ and activation time from 30 to 120 minutes. The optimal activation condition for iodine absorption was 90 minutes at $700^{\circ}C$ and by using the produced food waste charcoal, this study conducted an experiment on absorption of heavy metals (Cu and Cr) as changing pH of artificial wastewater and stirring time. As a result, pH 7 showed the highest heavy metal decontamination ratio and in terms of stirring time, it revealed balance adsorption after 10 minutes. This result can be particularly applied as basic data for recyclability of high concentration organic waste, by-products of food waste treatment facility, as an food waste charcoal.

• Journal of Korean Society of Forest Science
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• v.96 no.5
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• pp.533-538
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• 2007

This study was conducted in the spring of 2005 through personal interviews to examine the opinions of forest products manufacturers and consumers about the perspective of forest certification in South Korea and to characterize those consumers who expect the activation of a forest certification system in South Korea. Study results indicated that consumers showed more positive aspect for the activation of forest certification than forest products manufacturers. Respondents who had a negative view for establishing a forest certification system in South Korea pointed out a lack of customers' demand for certified wood products as the most important reason. Results also showed that, even when a forest certification system would be introduced as a possible policy for helping to attain sustainable forest management, it would take at least 5 to 10 years to establish a forest certification system in South Korea. To facilitate the establishment of the system, many respondents suggested that an increased public awareness of forest certification systems was the most required precedent condition, and government for manufacturers and forest management association for consumers had to certify forest management practices as a competent organization. A profile of consumers who expected the activation of a forest certification system would describe in relative terms as the highly educated female who interviewed in the city of Seoul and of the 20 age bracket. Although there were an increased public awareness and positive prospective of forest certification by consumers and forest products manufacturers, it is required to arouse much more interest of consumers about the system.

• Proceedings of the PSK Conference
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• 2001.04a
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• pp.182.2-183
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• 2001

• Journal of the Speleological Society of Korea
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• no.78
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• pp.1-8
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• 2007

The combination of mechano-chemical activation (MCA)and Self-propagating High-temperature Synthesis (SHS) has widened the technical possibilities for both methods. For YBCO systems the investigation showed that a short-term MCA of initial powders before SHS leads to single-phase and ultra-fine products. A new technique for preparation ultra-fine high-temperature superconductors (HTS) of YBCO composition with a grain size d <1m is developed using combination of MCA and SHS. The specific feature of the technique is formation of the $YBa_2Cu_3O_7-$ crystalline lattice directly from an X-ray amorphous state arising as a result of mechanical activation of the original oxide mixture. The technique allows the stage of formation of any intermediate reaction products to be ruled out. X-ray and magnetic studies of ultra-fine high temperature superconductors are carried out. Dimension effects associated with the microstructure peculiarities are revealed. A considerable enhancement of inter-grain critical currents is found to take place in the ultra-fine samples.

• Bulletin of the Korean Chemical Society
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• v.24 no.6
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• pp.829-831
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• 2003

Various theoretical studies of σ-bond activation of organic molecules by transition metal complexes arereviewed. In the homolytic σ-bond activation, the d orbital energy level of the central metal is an importantfactor, as well known. At the same time, the electron-withdrawing substituent which stabilizes the sp3 orbitalaccelerates the homolytic σ-bond activation. In the heterolytic C-H σ-bond activation of RH by $MXL_n$, the XHbond formation is an important driving force, where $MRL_n$ and HX are formed as products. The heterolytic σ-bond activation is also understood in terms of the electrophilic attack of the metal center to the substrate.

• Journal of Environmental Health Sciences
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• v.24 no.3
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• pp.70-76
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• 1998

Activation bacteria, identified from commercial microbial products, were applied to leachate treatment. Total seven strains of bacteria Enterobacteriaceae spp. (5), Bacillus sp. (1), Aeromonas sp. (1) were seeded in the leachate and cultured in the shaking incubator at 25$^{\circ}$C and 250 rpm. While cultured, they were sampled in given time intervals and the removal rates of SS, COD, BOD, T-N.and T-P were measured an indicators of leachate treatment. Through the screening test, four of 7 strains of bacteria were considered to be effective and they were named as "effective group". The capability of leachate treatment was observed on three different groups of bacteria single, effctive, and total mixed. The result showed that the removal rates of COD and SS for the total mixed group were 64 and 71% respectively. BOD removal rate was reached nearly 99% by seeding of effective griup and removal rates of T-P and T-N were 83 and 82% respectively. However seeding of single strain was less effective than that of any mixed group in leachate treatment.