Ramesh K.,Institute of Chemical and Engineering Sciences, Singapore |
Ramesh K.,Corporate R and nter |
Ling E.G.Y.,Nanyang Technological University |
Gwie C.G.,Institute of Chemical and Engineering Sciences, Singapore |
And 3 more authors.
Journal of Physical Chemistry C | Year: 2012
In the current study, we have synthesized calcium hydroxyapatite (CaHAP) from different phosphorus sources namely, NH 4H 2PO 4 and H 3PO 4. The structure of CaHAP was confirmed by XRD, FT-IR, and Raman characterization methods. The CaHAP was further modified with various anions such as WO 4 2-, SO 4 2-, and PO 4 3- with fixed content of 10 wt %. To understand the textural and structural properties, these samples were thoroughly characterized by N 2 physisorption, X-ray diffraction, Fourier transform infrared, Raman and thermogravimetry-differential thermal analysis methods. Ethanol adsorption at various temperatures was studied in detail using diffuse reflectance Fourier transform spectroscopic to unravel the formation and stability of surface species and the interaction of ethanol with CaHAP. The temperature programmed desorption of ethanol (ethanol-TPD) was performed to understand the stability, surface reactivity, and product distribution. The catalytic activity of the above catalysts was tested in ethanol conversion over a temperature range of 300-450 °C. © 2012 American Chemical Society.
Saitoh M.,Corporate R and nter |
Nakabayashi Y.,Corporate R and nter |
Itokawa H.,Corporate R and nter |
Itokawa H.,Toshiba Corporation |
And 7 more authors.
Digest of Technical Papers - Symposium on VLSI Technology | Year: 2010
We successfully reduced the parasitic resistance of nanowire transistors (NW Tr.) by raised S/D extensions with thin spacers (<10nm). Id variations are suppressed by spacer thinning and parasitic capacitance increase is minimal. By adopting <100> NW instead of <110> NW, Ion = 1mA/μm for Ioff = 100nA/μm is achieved without stress techniques. Long-L mobility (μ) was systematically studied by separating top and side channel μ. μ of <100> nFETs and <110> pFETs (potentially-high ?) largely degrade due to side-surface roughness. Gate stress and interface traps affect μ?of <110> nFETs and <110> pFETs, respectively. © 2010 IEEE.
Kim S.,Korea University |
Lee D.-W.,Korea University |
Lee J.Y.,Korea University |
Eom H.-J.,Korea University |
And 3 more authors.
Journal of Molecular Catalysis A: Chemical | Year: 2011
Mn-substituted La, Sr-hexaaluminate was studied as a catalyst for the catalytic combustion of pressure swing adsorption (PSA) offgas from a hydrogen station based on steam reforming of petroleum gas. The catalytic activity and thermal stability were tested under simulated PSA offgas condition and the catalysts were characterized by X-ray diffraction (XRD), inductively coupled plasma atomic emission spectroscopy (ICP-AES), CO2-temperature programmed desorption (TPD) and N2 physisorption for BET. All the LaxSr1-xMnAl11O19 catalysts prepared by co-precipitation method contained hexaaluminate structure as the major phase after 5 h calcination at 1200 °C. Partial substitution of La for Sr in SrMnAl11O19 increased the specific surface area and consequently the catalytic activity for oxidation of methane. The CO2 in the simulated PSA offgas was found to suppress the catalytic activity in methane oxidation if the catalyst had appreciable surface basicity. The most active catalyst, La0.6Sr0.4MnAl11O 19, retained its lattice structure and chemical composition even after 40-h thermal aging at 1000 °C under PSA offgas composition. © 2010 Elsevier B.V.
Park S.-H.,Catholic University of Daegu |
Suh D.,Corporate R and nter
Physica Status Solidi (B) Basic Research | Year: 2015
The light emission characteristics of ultraviolet (UV) AlxGa1-xN/AlN quantum well (QW) structures with the AlGaN delta-layer in the active region were investigated using the multiband effective-mass theory and non-Markovian gain model. In a wavelength range of 220-280nm, AlGaN/AlN QW structures with the ultrathin AlGaN layer are shown to have much larger light emission than conventional AlGaN/AlN QW structures. This can be explained by the fact that the internal field in the well is reduced and the optical matrix element is greatly enhanced with the inclusion of the low-bandgap AlGaN delta-layer. We expect that AlGaN/AlN QW structures with the ultrathin AlGaN layer can be used as a light source with a high efficiency in UV region. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Park H.,Gyeongsang National University |
Shin D.-C.,Corporate R and nter |
Shin S.-C.,Gyeongsang National University |
Kim J.-H.,Gyeongsang National University |
And 2 more authors.
Macromolecular Research | Year: 2011
New blue polymers having poly(arylenevinylene) derivatives composed of biphenylene-vinylene-m-(t-butylated) phenylene-vinylene and terphenylene- vinylene-m-(t-butylated)phenylene-vinylene in the main chain were synthesized by nickel catalyzed Yamamoto coupling and palladium-catalyzed Suzuki coupling reactions. The polymers showed good solubility in a common organic solvent and weight average molecular weights of 11,100 to 9,800 with a polydispersity index of 1.46-1.2. The polymers with a highly twisted structure exhibited deep blue emission with (λ max =465 for the homopolymer and λ max =457 nm for copolymer) as well as good thermal stability. Double layer light emitting diode devices fabricated using the obtained polymers as emitters showed blue emission with a maximum brightness of 18-225 cd/m 2. © 2011 The Polymer Society of Korea and Springer Netherlands.