• Journal of Korean Society for Atmospheric Environment
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• v.23 no.6
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• pp.699-707
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• 2007

This study was carried out to investigate the reaction characteristics of corona/catalyst hybrid $DeNO_x$ process. The experiments were performed by using the multi-staged pin-to-hole type corona reactor which is enable to control the pin-to-hole gap and to insert the catalyst. Also, used for this study, were catalysts which commercially used Pt, Pd and $TiO_2$, and oxygen and hydrocarbon ($C_2H_4$) as reagents. In the syn-gas test, at high temperatures in the range of $100{\sim}200^{\circ}C$, the corona-only $DeNO_x$ process did not reduce the $NO_x$ concentration effectively. However in the presence of ethylene and oxygen as reagents, the $NO_x$ removal efficiency was better at these high temperatures than corona-only $DeNO_x$ process. In addition, coronal catalyst hybrid process with $TiO_2$ showed more efficiency of $NO_x$ removal than Pt and Pd catalyst, because the $TiO_2$ catalyst was more active than Pt and Pd catalyst to converse the $NO_2$ to $HNO_3$. Furthermore, at the condition of real diesel exhaust gas, the $DeNO_x$ efficiency of corona/catalyst hybrid process was not good at higher reaction temperature and plasma density.

• Analytical Science and Technology
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• v.8 no.4
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• pp.561-568
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• 1995

Two methods, precipitation and ultrafiltration, were applied in order to recover platinum group metals(PGM) by complexing them with water-soluble polyelectrolytes, e.g., polyethyleneimine [PEl], poly(2-vinylpyridine) [2-PVP], poly (4-vinylpyridine) [4-PVP], and poly (styrene sulfonic acid) [PSSA]. In the precipitation method, the PGM-polyelectrolyte complex that was formed by mixing first with polybase, e.g.,4-PVP at pH 1 was precipitated by further mixing with polyacid, e.g., PSSA. However, the recovery of PGM obtained by this method was not quantitative(less than 70%). The "sandwiching" binding between the metal anions and two polyelectrolytes was examined by X-ray photoelectron spectroscopy(XPS). The XPS studies indicated that the PGM atom was bound with the acdic and basic polyelectrolyte via its oxygen and nitrogen atom, respectively. The recovery of PGM using polyelectrolyte was further studied by ultrafiltration methods as follows : The PGM ions, eomplexed at pH 1 with polyelectrolyte, allowed the applicntion of membrane filtration by virtue of the great differences in molecular weights between PGM and other low molecular weight species. By applying this method, Pd and Pt (ca. $10^{-4}M$) were selectively separated almost quantitatively from coexisting metal ions, e.g., $Cu^{2+}$ and $Ni^{2+}$. The EPR spectra and viscosity measurements indicated that these polyelectrlytes were not bound to $Cu^{2+}$ and $Ni^{2+}$ ions at this pH, which provided the basis for selective separation of PGM(Pd, Pt and Rh) from these coexisting ions.

• Proceedings of the Ginseng society Conference
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• 1988.08a
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• pp.151-155
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• 1988

The present study was undertaken to determine the inhibitory effects of orally administered ginseng saponins(SP), protopanaxadiol saponins (PD), and protopanaxatriol saponins(PT) on the development of morphine-induced tolerance and physical dependence in mice. The study also sought to determine the hepatic glutathione contents. which are closely related to the degree of detoxification of mine the effects of GS on morphine 6-dehydrogenase, which catalyzes the production of morphinone from morphine, and the roles of spinal descendign inhibitory systems in the production of antagonism. The results of the present study showed that GS, PD and PT administered orally inhibited the development of morphine induced tolerance and dependence. GS. PD and PT inhibited the reduction of hepatic glutathione concentration in mice treated chronically with morphine and the activity of morphine 6-dehydrogenase, and the activation of spinal descending inhibitory systems was inhibited by GS. So we hypothesized that the results were partially due to the dual action of the test drugs, the inhibition of morphinone production and the activated formation of morphinone-glutathinone conjugation, and the inhibition of the activatin of apinal descending inhibitory systems and the others.

• Journal of Sensor Science and Technology
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• v.6 no.6
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• pp.476-482
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• 1997

A portable electronic nose system has been fabricated and characterized using an oxide semiconductor gas sensor array and pattern recognition techniques such as principal component analysis and back-propagation artificial neural network. The sensor array consists of six thick-film gas sensors whose sensing layers are Pd-doped $WO_{3}$, Pt-doped $SnO_{2}$, $TiO_{2}-Sb_{2}O_{5}-Pd$-doped $SnO_{2}$, $TiO_{2}-Sb_{2}O_{5}-Pd$-doped $SnO_{2}$ + Pd coated layer, $Al_{2}O_{3}$-doped ZnO and $PdCl_{2}$-doped $SnO_{2}$. The portable electronic nose system consists of an 16bit Intel 80c196kc as CPU, an EPROM for storing system main program, an EEPROM for containing optimized connection weights of artificial neural network, an LCD for displaying gas concentrations. As an application the system has been used to identify 26 carbon monoxide/hydrocarbon (CO/HC) car exhausting gases in the concentration range of CO 0%/HC 0 ppm to CO 7.6%/HC 400 ppm and the identification has been successfully demonstrated.

• Journal of the Semiconductor & Display Technology
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• v.7 no.4
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• pp.41-44
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• 2008

NiSi is less stable than the previously-used $CoSi_2$ at high temperature. Some noble metals, such as Pd and Pt, have been added to NiSi to improve its thermal stability. We employed a first principles calculation to understand the Pd segregation at the interface. An orthorhombic structure of NiSi was used to construct an orthorhombic-NiSi/Si (010). Lattice parameters along a- and c-axes in orthorhombic-NiSi were matched with those of Si for epitaxy contact. The optimized $1\times4\times1$ orthorhombic-NiSi (010) and $1\times2\times1$ Si (010) superstructures were put together to construct the orthorhombic-NiSi/Si (010), and the superstructure was relieved in calculation to minimize its total free energy. The optimized interface thickness of the superstructure was $1.59\AA$. Pd atom was substituted in Ni and Si sites located near interface. Both Ni and Si sites located at the interface were favorable for Pd substitution.

• Bulletin of the Korean Chemical Society
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• v.16 no.6
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• pp.479-483
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• 1995

The synergistic extraction of palladium(Ⅱ) was studied with 1,2-dichloroethane containing thenoyltrifluoroacetone (TTA; HA) and tri-n-octylphosphine oxide (TOPO; S). The main composition of synergistic adduct extracted into 1,2-dichloroethane phase was found to be PdA2S2. The equilibrium constants of the synergistic reaction were calculated. The application of this method to synthetic mixture for the separation of Pd from Pt was developed.

• Proceedings of the Korean Magnestics Society Conference
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• 2002.12a
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• pp.196-197
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• 2002

보편적으로 알려진 CoCr합금 수직기록매체의 경우, 기록매체에서 출력되는 신호의 크기가 작고 열적안정성이 떨어지는 문제점이 있다. 이러한 CoCr합금 수직기록매체를 대체할 기록 매체로 Co/Pd 다층박막에 관한 연구를 수행하였다. Co/Pt 및 Co/Pd계 다층박막은 수직배향성을 가지며 일찍부터 Magneto-optical 매체로 연구되었다. Co/Pd 다층박막은 자성재료와 비자성재료를 약 2~3개 원자층의 박막 두께(10$\AA$이하)로 번갈아 가며 진공증착한 것으로. CoCr합금계 수직기록매체에 비해 열적안정성이 뛰어나고 수직방향의 잔류 자화가 큰 장점을 가지고 있다. (중략)

• Journal of Ginseng Research
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• v.22 no.4
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• pp.274-283
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• 1998

It has generally been accepted that quality of ginseng should be determined not by the content of a single component but by composition and balance of total active principles. However, there still can be an exception with a product in which a given ginsenoside is used for the treatment of a specific disease. Although ginsenosides have been regarded to be major active components of ginseng and employed as index components for the quality control, it does not consistent with the traditional concept on ginseng quality creterion; main root has been more highly appreciated than the lateral or fine root. Content of ginsenosides in the lateral or fine root is much higher than that in main root. However, the ratio of protopanaxadiol (PD) and protopanaxatriol (PT) saponins existing in various part of ginseng root is greatly different. The ratio of PD/PT saponins in main root is well balanced but the thinner the root is the higher the ratio. Thus far, a total of 34 different kinds of ginsenosides have been isolated from Korean (red) ginseng, and their pharmacological activities were elucidated partly. Interestingly, different ginsenoside shows similar or contrary effects to each other in biological systems, thus indicating the significance of absolute content of single ginsenoside as well as compositional patterns of each ginsenoside. Therefore, pharmacological activities of ginseng should be determined as a wholly concept. In these regards, standardization of ginseng material (fresh ginseng root) should be preceded to the standardization of ginseng products because ginsenoside content and non-saponin active principles such as polysaccharides and nitrogen (N)-containing compound including proteins are significantly different from part to part of the root. In other words, the main root contains less ginsenosides than other lateral or fine roots. Contents of polysaccharides and N-containing compound in main root is higher. However, the quality control of ginseng products focused on non-saponin compounds has limitation in applying to the analytical method, because of the difficult chemical analysis of these compounds. Content of ginsenosides, and ratios of PD/PT and ginsenoside Rb,/Rg, are inversely proportional to the diameter of ginseng root. Therefore, these can be served as the chemical parameters for the indirect method of evaluating from what part of the root does the material originate. Furthermore, contents of polysaccharides and N-containing compounds show inverse relationship to saponin content. Therefore, it seems that index for analytical chemistry of saponin can be applied to the indirect method of evaluating not only saponin but also non-saponin compounds of ginseng. From these viewpoints, it is strongly recommended that quality of ginseng or ginseng products be judged not only by the absolute content of given ginsenoside but also by varieties and compositional balance of ginsenosides, including contents of non-saponin active principles.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.7
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• pp.472-478
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• 2013

Cu and Cr as a base metal and Pt, Pd as a supportive metal were selected for improving adsorption capacity of activated carbon fiber in eliminating especially targeted VOCs. Preparing variables such as metal loading, loading temperature, loading hours and kinds of loaded metals were changed. Properties measurement was carried out by SEM (scanning electron microscope), XRF (x-ray fluorescence analysis) and EDX (Energy Dispersive X-ray spectrometer) and adsorption capacity evaluation were also performed by gas analyzer. Under this study, the adsorption capacity of complex metal loaded activated carbon fiber was improved positively than that of single metal loaded activated carbon fiber. And we found that the best conditions for metal loading were 5 hours loading time at $100^{\circ}C$ and the adsorption capacity was enhanced almost double compared with other condition based activated carbon fiber. Cu-Cr-Pt-Pd loaded activated carbon fiber showed the best adsorption capacity. Also we confirmed that more than 0.5 second is necessary for adsorbate diffusion and adsorption over activated carbon fiber.

• Journal of the Korean Society of Food Science and Nutrition
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• v.11 no.3
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• pp.81-86
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• 1982

Ginseng saponins separated from Panax ginseng C.A. Meyer were analyzed by high-performance liquid chromatography using a carbohydrate analysis column. The effect on the resolution and retention time of each ginsenosides, as well as the addition effect of n-butanol on a acetonitrile/water system, was examined using various proportions of acetonitrile/water system (80/20-94/6) which have been used with typical solvent of carbohydrate analysis column. The retention time of each ginsenosides was greatly affected by the compositions and mixture proportions of the mobile phase and also markedly increased as the proprotion of acetonitrile in mobile phase increased. It was proved that acetonitrile/water system (80/20) and acetonitrile/water/n-butanol system (86/14/10) were very effective mobile phases for diol and triol sapoin analyses, respectively. According to the result obtained by this method, the PT/PD ratios of white and red ginseng saponins were 0.401 % and 0.561 %, respectively. Red ginseng increased PT/PD ratio, compared with white ginseng. This is attributed to the change of saponin pattern by processing method and the change of PT/PD ratio would greatly influence on the biochemical and pharmacological effects of ginseng and its products.