• Journal of Electrochemical Science and Technology
• /
• v.4 no.4
• /
• pp.163-170
• /
• 2013

Tantalum anodic oxide film was prepared in citric acid solution of various concentrations and the prepared Ta anodic oxide film was characterized by various electrochemical techniques and X-ray photoelectron spectroscopy (XPS). The prepared Ta anodic oxide film showed typical n-type semiconducting properties and the dielectric properties were strongly dependent on the citric acid concentration. The variation of electrochemical and electronic properties was explained in terms of electrolyte anion incorporation into the anodic oxide film, which was supported by XPS measurements.

• Journal of Advanced Marine Engineering and Technology
• /
• v.41 no.2
• /
• pp.146-149
• /
• 2017

Si clusters generated during the plasma chemical vapor deposition (CVD) process have a great influence on the quality of the fabricated films. In particular, in hydrogenated amorphous silicon thin films (a-Si:H) used for thin film solar cells, Si clusters are mainly responsible for light-induced degradation. In this study, we investigated the amount of clusters incorporated into thin films using a quartz crystal microbalance (QCM) and specially designed cluster eliminating filters, and investigated the effect of the DC grid mesh in preventing cluster incorporation. Experimental results showed that as the applied voltage of the grid mesh, which is placed between the electrode and the QCM, decreased, the number of clusters incorporated into the film decreased. This is due to the electrostatic force from the grid mesh bias, and this method is expected to contribute to the fabrication of high-quality thin films by preventing Si cluster incorporation.

• Korean Journal of Pharmacognosy
• /
• v.4 no.2
• /
• pp.67-70
• /
• 1973

In Peucedanum japonicum and Aster tataricus L. chlorogenic acid was identified by methods of P.P.C. and T.L.C. $L-Phenylalanine-U-^{14}C\;and\;sodium\;acetate-2-^{14}C$ were administered to Peucedanum japonicum, $L-Tyrosine-U-^{14}C$ to Aster tataricus and $caffeic\;acid-carboxyl-^{14}C\;and\;L-tyrosine-U-^{14}C$ to Fagopyrum esculentum $M_{OENCH}$. The incorporation of each compound into chlorogenic acid was compared. $L-Phenylalanine-U-^{14}C$ showed higher incorporation to chlorogenic acid than sodium $acetate-2-^{14}C$ in Peucedanum japonicum. $Caffeic{\;}acid-carboxyl-^{14}C$ was higher to chlorogenic acid than $L-tyrosine-U-^{14}C$ in Fagopyrum esculentum. $L-Tyrosine-U-^{14}C$ was comparatively low in Aster tataricus.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.22 no.5
• /
• pp.213-217
• /
• 2012

Carbon coils could be synthesized on nickel catalyst layer-deposited silicon oxide substrate using $C_2H_2$ and $H_2$ as source gases under thermal chemical vapor deposition system. By the incorporation of $SF_6$ additive in cyclic modulation manner, the dominant formation of the nanosized carbon coils could be achieved with maintaining the minimized sulfur additive amount. The geometry variation of the as-grown carbon coils, such as linear type, microsized coil type, wavelike nanosized coil type, and nanosized coil type, were investigated according to the different cyclic modulation manner of $SF_6$ flow. $SF_6$ gas incorporation develops the coil-type geometry. Furthermore, the higher flow rate of $SF_6$ gas increased the amount of the nanosized carbon coils. The slightly increased etching ability by $SF_6$ addition seems to be the cause for these results.

• Journal of the Korean Applied Science and Technology
• /
• v.31 no.2
• /
• pp.225-230
• /
• 2014

Several nitrile-functionalized ionic liquids have been prepared and characterized. An attempt was made to systematically characterize nitrile-functionalized ionic liquids on the basis of a few kinds of cations and anions. The detailed comparison of the differences in physicical characteristics such as UV-Vis spectroscopy, thermal stability, viscosity, solubility property, and electrochemical property before and after incorporation of a nitrile group were studied. The results showed that the incorporation of a nitrile group to cations could result in remarkable changes in these properties.

• Korean Journal of Pharmacognosy
• /
• v.4 no.4
• /
• pp.185-188
• /
• 1973

In Cnidium officinale $M_{AKINO}$ and Platycodon grandiflorum A. $D_E\;C_{ANDOLE}$, chlorogenic acid was identified by Rf values, color reactions on paper chromatograms and UV-absorption spectra of the eluate of phenolic spots. And isochlorogeni acid-like substance was also found in the former. $1-Phenylalanine-U-C^{14}$ and sodium $acetate-2-C^{14}$ werse fed to both plants and their incorporation ratio to chlorogenic acid and isochlorogenic acid-like substance was compared. Phenylalanine was better precursor for chlorogenic acid in both plants than acetate. But acetate showed higher incorporation ratio to isochlorogenic acid-like substance in Cnidium officinale than that of phenylalanine.

• Communications of Mathematical Education
• /
• v.20 no.3 s.27
• /
• pp.361-372
• /
• 2006

This study was extended as one of the properties of isosceles triangles to polygons(n-angles) by conjectures-proofs-reputations-reformations and developed teaching-learning materials which can be used in high-level classes for middle and high school students.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2018.05a
• /
• pp.17-18
• /
• 2018

With the technological advancement of the construction industry, construction materials with future direction appeared. In Korea, LEFC(Light Emotion Friendly Concrete) has been developed and studied, which has improved labor productivity and economic efficiency over semi-transparent concrete by introducing transparent plastic rods into concrete matrix. However, there is a problem in that the bending performance is lowered according to the insertion of the rod and the bending performance is different according to the light transmission direction. In this study, the incorporation of PVA fibers in the direction of light transmission was increased and the change of flexural performance according to the interval of light transmission was examined.

• Journal of Sensor Science and Technology
• /
• v.13 no.6
• /
• pp.446-453
• /
• 2004

A portable electronic tongue (E-Tongue) system using an array of ion-selective electrode (ISE) and personal digital assistants (PDA) for recognizing and analyzing food and drink have been designed. By the employment of PDA, the complex algorithm such as fuzzy c-means algorithm (FCMA) could be used in E-Tongue, PUMA could iteratively solve the cluster centers of pre-determined standard patterns. And the membership between the standard patterns and unknown pattern could be analyzed easily by the present E-Tongue combined with PDA.

• Bulletin of the Korean Chemical Society
• /
• v.33 no.1
• /
• pp.153-158
• /
• 2012

The hydrogenation of $AlB_2$-type BaGaGe exhibits a metal to insulator (MI) transition, inducing a puckering distortion of the original hexagonal [GaGe] layers. We investigate the electronic structure changes associated with the hydrogen-induced MI transition, using extended H$\ddot{u}$ckel tight-binding band calculations. The results indicate that hydrogen incorporation in the precursor BaGaGe is characterized by an antibonding interaction of $\pi$ on GaGe with hydrogen 1s and the second-order mixing of the singly occupied antibonding $\pi^*$ orbital into it, through Ga-H bond formation. As a result, the fully occupied bonding $\pi$ band in BaGaGe changes to a weakly dispersive band with Ge pz (lone pair) character in the hydride, which becomes located just below the Fermi level. The Ga-Ge bonds within a layered polyanion are slightly weakened by hydrogen incorporation. A rationale for this is given.