• Membrane and Water Treatment
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• v.9 no.6
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• pp.463-471
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• 2018

The present paper deals with the liquid-liquid extraction and flat sheet supported liquid membrane studies of Pd(II) separation from nitric acid medium using a novel synthesized ligand, namely, N,N,N',N'-tetraethyl-2,2-thiodiethanthiodiglycolamide (TETEDGA). The effect of various diluents and stripping reagents on the extraction of Pd(II) was studied. The liquid-liquid extraction studies showed complete extraction of Pd(II) in ~ 5 min. The influence of nitric acid and TETEDGA concentration on the distribution of Pd(II) has been investigated. The increase in nitric acid concentration resulted in increase in extraction of Pd(II). Stoichiometry of the extracted species was found to be $Pd(NO_3)_2{\cdot}TETEDGA$ by slope analysis method. Extraction studies with SSCD solution showed negligible uptake of Pt, Cr, Ni, and Fe, thus showing very high selectivity and extractability of TETEDGA for Pd(II). The flat sheet supported liquid membrane studies showed quantitative transport of Pd(II), ~99%, from the feed ($3M\;HNO_3$) to the strippant (0.02 M thiourea diluted in $0.4M\;HNO_3$) using 0.01 M TETEDGA as a carrier diluted in n-dodecane. Extraction time was ~160 min. Parameters such as feed acidity, TETEDGA concentration in membrane phase, membrane porosity etc. were optimized to achieve maximum transport rate. Permeability coefficient value of $2.66{\times}10^{-3}cm/s$ was observed using TETEDGA (0.01 M) as carrier, at 3 M, $HNO_3$ feed acidity across $0.2{\mu}m$ PTFE as membrane. The membrane was found to be stable over five runs of the operation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.99-102
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• 1997

An electronic nose system is an instrument designed far mimicking human olfactory system. It consists generally of gas (odor) sensor array corresponding to olfactory receptors of human nose and artificial neural network pattern recognition technique based on human biological odor sensing mechanism. Considerable attempts to develop the electronic nose system have been made far applications in the fields of floods, drinks, cosmetics, environment monitoring, etc. A portable electronic nose system has been fabricated by using oxide semiconductor gas sensor array and pattern recognition technique such as principal component analysis (PCA) 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$_3$-Pd-doped SnO$_2$ TiO$_2$-Sb$_2$O$_{5}$-Pd-doped SnO$_2$+Pd filter layer, A1$_2$O$_3$-doped ZnO and PdCl$_2$-doped SnO$_2$. As an application the system has been used to identify CO/HC car exhausting gases and the identification has been successfully demonstrated.d.

• Transactions of the Korean hydrogen and new energy society
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• v.15 no.4
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• pp.317-323
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• 2004

We fabricated a MISFET using Pd/NiCr gate for the detecting of hydrogen gas in the air and investigated its electrical characteristics. To improve stability and high concenntration sensitivity and remove the blister generated by the penetration of hydrogen atoms Pd/NiCr catalyst gate metal are used as dual gate. To reduce the gate drift voltage caused by the inflow of hydrogen, the gate insulators of sensing and reference FFET were constructed with double insulation layers of silicon dioxide and silicon nitride. The hydrogen response of MISFET were amplified with the difference of gate voltages of both MISFET. To minimize the drift and the noise, we used a OP177 operational amplifier. The sensitivity of the Pd/NiCr gate MISFET was lower than that of Pd/Pt gate MISFET, but it showed good stability and ability to detect high concentration hydrogen up to 1000ppm.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.145-145
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• 2000

M-CeO2 (M : noble metal) catalysts have been widely studied as three-way catalysts and methanol synthesis catalysts. Ceria is thought to play a number of roles in these catalysts. The Ce(IV)/Ce(III) redox pair may store/release gases under oxidizing/reducing conditions, extending the operational window. Additionally, metal-ceria interactions lead to several effects, including the dispersion of the active components and promoting the activation of molecules such as CO or NO. Pd is a promising component to current TWC formulations and behaves particularly well when compared with Pt and Rh-based catalysts for low-temperature oxidation of Co and hydrocarbon. However the effect of Pd-ceria interactions on the physicochemical properties of Pd and the redox properties of Ce is not elucidated yet. In order to know exactly about the metal-ceria interactions, the model study are expecting to give a better environment, resulting in the wide use of the surface science tools. The substrate was Si(100) wafer, on which Ta metal was sputtered as a thickness of 100nm. The CeO2 thin film of 30nm was deposited by using the magnetron sputtering. Spin coating and magnetron sputtering methods were used to make the Pd thin film layer. The prepared sample was investigated by in-situ XPS, AES, SEM and AFM analysis.

• Journal of Ginseng Research
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• v.23 no.1 s.53
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• pp.44-49
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• 1999

Cu/Zn superoxide dismutase (SOD1) is a protective enzyme responsible for the dismutat ion of superoxide radicals within the cell by converting superoxide radicals to oxygen and hydrogen peroxide, which is in turn changed to oxygen and water by catalase. Previously, we reported that the panaxadiol (PD) and its ginsenoside $Rb_2$ induced the expression of SOD1 gene through AP2 binding site and its induction. Here, we examined the effect of subfractions of panaxadiol ginsenosides, which were extracted from different parts of ginseng root that possess various ratios of panaxadiol to panaxatriol, on the induction of SOD1 gene expression. To explore this possibility, the upstream regulatory region of SOD1 was linked to the chloramphenicol acetyl transferase (CAT) structural gene and introduced into human hepatoma HepG2 cells. We observed that the transcriptional activation of SOD1 was proportional to the contents ratio of panaxadiol ginsensides. Consistent with this results, the total extract portion prepared from the finely-hairy root, which contains the higher ratio of panaxadiol to panaxatriol about 2.6, increased the SODl transcription about 3 fold. This results suggest that the panaxadiol fraction could induce the SOD1 and total extract of the ginseng finely-hairy root would be a useful material as a functional food for the SOD1 inducer.

• Bulletin of the Korean Chemical Society
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• v.23 no.5
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• pp.674-678
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• 2002

The dehydrogenation of propane to propylene has been studied in an isothermal high-temperature shell-and-tube membrane reactor containing a Pd-coated ${\psi}$-Al2O3 membrane and a Pt/K/Sn/Al2O3 packed catalyst . A tubular Pd-coated ${\psi}$-Al2O3 membrane was prepared by an electroless plating method. This membrane showed high hydrogen to nitrogen permselectivities (PH2N2 = 10-50) at 400 $^{\circ}C$ and 500 $^{\circ}C$ with various transmembrane pressure drops. The employment of a membrane reactor in the dehydrogenation reaction, which selectively separates hydrogen from the reaction mixture along the reaction path, can greatly increase the conversion and enable operation of the reactor at lower temperatures. High hydrogen permselectivity has been confirmed as a key factor in determining the reactor performance of conversion enhancement.

• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.719-722
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• 2003

This work investigates the device degradation p-channel PD SOI devices at various applied voltages as well as stress temperatures with respect to Body-Contact SOI (BC-SOI) and Floating-Body SOI (FB-SOI) MOSFETs. It is observed that the drain current degradation at the gate voltage of the maximum gate current is more significant in FB-SOI devices than in BC-SOI devices. For a stress at the gate voltage of the maximum gate current and elevated temperature, it is worth noting that the $V_{PT}$ Will be decreased by the amount of the HEIP plus the temperature effects. For a stress at $V_{GS}$ = $V_{DS}$ . the drain current decreases moderately with stress time at room temperature but it decreases significantly at the elevated temperature due to the negative bias temperature instability.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1994.05a
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• pp.98-102
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• 1994

천연가스의 주성분인 순수 메탄에 대한 촉매 산화반응은 Pd촉매가 가장 양호하나 LP가스의 주성분인 프로판에 대해서는 Pt촉매가 가장 양호한 결과를 보였다. 그러나 유황 피독된 Pd촉매는 메탄에 대해 영구피독 현상을 보였고, fresh한 Pd촉매는 연료 중 미량의 유황분량에 의해 반응 개시온도가 지연되는 경향을 보였다. 이와 같은 촉매독 영향이 적은 Rh촉매버너를 개발하여 8000시간 이상 성공적인 연소 실험을 하고 있으며 C 방적의 염색 시험기에 적응 실험한 결과 기존의 적외선 전기 건조기에 비해 에너지 절감은 약30-40%를 기하였고 연료비는 70-80%의 절약효과를 얻었다.

• Proceedings of the Korean Magnestics Society Conference
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• 2007.05a
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• pp.33.1-33.1
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• 2007

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2008.04a
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• pp.155-160
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• 2008