• Journal of Pharmaceutical Investigation
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• v.18 no.1
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• pp.15-21
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• 1988

An inclusion complex of phenytoin (PT) with ${\beta}-cyclodextrin\;({\beta}-CyD)$ in molar ratio of 1 : 1 was prepared, and the interaction between host and guest molecules was confirmed by infrared spectrometry, differential scanning calorimetry and X-ray diffractometry. Suppositories were prepared by the fusion method. PT and $PT-{\beta}-CyD$ complex were added to PEG 1540 and Witepsol H-15 under the vigorous stirring at $40^{\circ}C$. Content uniformity was tested for different formulations of the PT suppositories. The release rates were dependent on the K.P. V dissolution apparatus and the dialyzing tubing method. Then, the release rates were increased in the following order: $PT-{\beta}-CyD$ complex in PEG 1540>PT in PEG 1540>$PT-{\beta}-CyD$ complex in Witepsol H-15>PT in Witepsol H-15. The area under the curve and maximum blood concentration after rectal administration were increased in the following order: $PT-{\beta}-CyD$ complex in PEG 1540>PT in PEG 1540>$PT-{\beta}-CyD$ complex in Witepsol H-15>PT in Witepsol-15.

• Journal of the Korean Electrochemical Society
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• v.24 no.4
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• pp.113-119
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• 2021

In this study, impurity free V^3.5+ electrolytes were prepared using formic acid as a reducing agent and PtD/C as a catalyst and it was applied to VRFB. The well-oriented 3D dendrite structure of the PtD/C catalyst showed high catalytic activity in formic acid oxidation reaction and vanadium reduction reaction. As a result, the conversion ratio of electrolyte using the PtD/C was 2.73 mol g^-1 h^-1, which was higher than that of 1.67 mol g^-1 h^-1 of Pt/C prepared by the polyol method. In addition, in the VRFB charging and discharging experiment, the V^3.5+ electrolyte produced by the catalytic reaction showed the same performance as the standard V^3.5+ electrolyte prepared by the electrolytic method, thus proving that it can be used as an electrolyte for VRFB.

• Journal of the Korean Chemical Society
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• v.41 no.6
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• pp.277-283
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• 1997

Platinum(II) complexes(where, $[Pt(L)_2X_2]$; L=isoxazole(isox), 3,5-dimethylisoxazole(3,5-diMeisox), 3-methyl,5-phenylisoxazole(3-Me,5-Phisox), and 4-amino-3,5-dimethylisoxazole(4-ADI); X=Cl, Br) with planar ligands are investigated on antitumor activity by MM2 and EHMO calculations. It was found that, the net atomic charges of the halogen atoms in all of cis-, trans-isomers are greater than that of the nitrogen with planar form, indicating that ionic character of Pt-X bond is greater than that of Pt-N. Also, the ${\sigma}MO$ energy level($E{\sigma}_{(Pt-X)}$) of the interaction between $d_{x2-y2}$ orbital of Pt atom and $p_x$ orbital of X found to be higher than that of between $d_{x2-y2}$ orbital of Pt atom and $p_x$ orbital of N about all the complexes. It is found that bond strength of between Pt and X atom is weaker than that of between Pt and N atom. The ${\sigma}MO$ energy level($E{\sigma}_{(Pt-X)}$) of trans- complexes found to be higher than that of cis- complexes, as a result of bond strength of Pt-X in cis- and trans-complexes, for all the complexes. The degree of dissociation of X atom in Pt-X bond for trans-complexes are related to antitumor activity and the logIA value of inhibitory activity coefficient(IA).

• Journal of Electrochemical Science and Technology
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• v.11 no.1
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• pp.84-91
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• 2020

The PtBi/C and PtBiPd/C electrocatalysts were synthesized via the irreversible adsorption of Pd and Bi ions precursors on commercial Pt/C catalysts. XRD and XPS revealed the formation of an alloy structure among Pt, Bi, and Pd atoms. The current of direct formic acid oxidation (I_d) increased ~ 8 and 16 times for the PtBi/C and PtBiPd/C catalysts, respectively, than that of commercial Pt/C because of the electronic, geometric, and third body effects. In addition, the increased ratio between the current of direct formic acid oxidation (I_d) and the current of indirect formic acid oxidation (I_ind) for the PtBi/C and PtBiPd/C catalysts suggest that the dehydrogenation pathway is dominant with less CO formation on these catalysts.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.18 no.3
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• pp.105-108
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• 2008

Four different thin films were made by depositing PZ and PT in different stacking sequences. PZ and PT phases are preferably co-existed in sample A and C that are annealing after each coatings. The sample B and D, on the other hands, have tendency toward the PZT phase after co-firing the sample. The sample B that started from PT stacking first was more stable PZT phase than that of PZ first sample D.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.164-164
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• 2000

Since Au-Pt alloys have various atomic structures depending upon composition and annealing temperature, it is very interesting to investigate the electronic structures of alloys. We studied the changes of the electronic structure I the Au-Pt alloys by x-ray absorption near edge spectroscopy (XANES). Two kinds of Au-Pt alloy samples were prepared by arc melting methods and ion-beam-mixing technique. The Pt L2, 3-edge and Au L2, 3-edge X-ray absorption spectra (XPS) were measured with the electron yield mode detector at the 3C1 beam line of the Pohang Light Source (PLS). It was found that there was a substantial decrease in the area of the Pt L2, 3 white lines compared with that of pure Pt. The observed decrease in white line area was attributed to an increase in the number of pure Pt. The observed decrease in white line area was attributed to an increase in the number of 5d-electrons at the Pt site upon alloy formation. However, the Au L2, 3 edge spectra for Au-Pt alloys are all similar to that of pure Au. This implies that the 5d hole count of Au is not changed by alloy formation with Pt.

• Bulletin of the Korean Space Science Society
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• 1995.10a
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• pp.23-23
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• 1995

No Abstract, See Full Text

• Proceedings of the Korean Magnestics Society Conference
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• 2012.11a
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• pp.172-172
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• 2012

A Pt-skin $Pt_3Ni$(111) surface was reported to show high catalytic activity. In this study, we investigated the magnetic properties and electronic structures of the various oriented surfaces of bulk-terminated and Pt-segregated $Pt_3Ni$ by using a first-principles calculation method. The magnetic moments of Pt and Ni are appreciably enhanced at the bulk-terminated surfaces compared to the corresponding bulk values, whereas the magnetic moment of Pt on the Pt-segregated $Pt_3Ni$(111) surface is just slightly enhanced because of the reduced number of Ni neighboring atoms. Spin-decomposed density of states shows that the dz2 orbital plays a dominant role in determining the magnetic moments of Pt atoms in the different orientations. The lowering of the d-band center energy (-2.22 eV to -2.46 eV to -2.51 eV to -2.65 eV) in the sequence of bulk-terminated (100), (110), (111), and Pt-segregated (111) may explain the observed dependence of catalytic activity on surface orientation. Our d-band center calculation suggests that an observed enhanced catalytic activity of a $Pt_3Ni$(111) surface originates from the Pt-segregation.

• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1358-1360
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• 1997

In this paper, the performance of Pt/$WO_3$ and Pt-$WO_3$ electrodes was studied for the direct methanol fuel cell. The characteristics of Pt/$WO_3$ electrode which was prepared by using electrodeposition method was tested with half-cell experiment. The characteristics of Pt-$WO_3$/C electrode which was Prepared by using freeze-drying method was tested with a single cell experiment. The performance of DMFC single cell which was prepared by Pt-$WO_3/C$ and Pt/C showed a current density of $32mA/cm^2$ at $110^{\circ}C$ & 0.3V(0.5mg Pt/$cm^2$).

• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.749-752
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• 1995

Electronic structures of the Heusler compounds, XMnSb (X=Ni, Pd, and Pt) are investigated systematically by using the linearized muffiu-tin orbital (LMTO) band method. LMTO band calculations yield that, by including the spinorbit interactions, the NiMnSb and PtMnSb are half-metallic, while PdMnSb is normal metallic at the experimental lattice constant. The effect of the spin-orbit interaction is substantial in PtMnSb, in contrast to NiMnSb and PdMnSb. The calculated X d and Mn 3d angular momentum projected local density of states's reveal that the hybridization between the Mn 3d X d states increases from X = Pt to Pd and Ni.