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131.
Choi HC Bae SY Jang WS Park J Song HJ Shin HJ Jung H Ahn JP 《The journal of physical chemistry. B》2005,109(5):1683-1688
Nitrogen (N)-doped carbon nanotubes (CNTs) were heated to 1000 degrees C under an ultrahigh vacuum. X-ray photoelectron spectroscopy (XPS) and X-ray absorption near-edge structure (XANES) reveal three different N structures; graphitelike, pyridine-like, and molecular N(2). The vibrationally resolved XANES peaks of N(2) were first observed, suggesting the existence of molecular N(2) as intercalated and trapped forms. The annealing process can decrease the average N content from 6.3 at. % to 3.3 at. %, mainly by releasing molecular N(2). Electron energy-loss spectroscopy (EELS) confirms that the annealing releases molecular N(2) from the CNTs. 相似文献
132.
The methanol-catalyzed double-proton transfer of photoexcited 7-azaindole in the free cores of solvation-restricted reverse micelles takes place on the time scale of 90 ps, even shorter than in bulk methanol. This anomalous rate increase with a large kinetic isotope effect of 5 experimentally proves the widely discussed two-step model for the overall reaction of solvent-mediated proton transfer. On the other hand, the molecules in the bound layers and in the headgroup layers relax in 900 and 6000 ps, respectively, without going through proton transfer. The tautomerization and the relaxation of excited 7-azaindole can be exploited to probe the nanopools of methanol reverse micelles. 相似文献
133.
Aliu E Andringa S Aoki S Argyriades J Asakura K Ashie R Berns H Bhang H Blondel A Borghi S Bouchez J Burguet-Castell J Casper D Cavata C Cervera A Cho KO Choi JH Dore U Espinal X Fechner M Fernandez E Fukuda Y Gomez-Cadenas J Gran R Hara T Hasegawa M Hasegawa T Hayashi K Hayato Y Helmer RL Hill J Hiraide K Hosaka J Ichikawa AK Iinuma M Ikeda A Inagaki T Ishida T Ishihara K Ishii T Ishitsuka M Itow Y Iwashita T Jang HI Jeon EJ Jeong IS Joo K Jover G Jung CK Kajita T Kameda J Kaneyuki K Kato I 《Physical review letters》2005,94(8):081802
We present results for nu(mu) oscillation in the KEK to Kamioka (K2K) long-baseline neutrino oscillation experiment. K2K uses an accelerator-produced nu(mu) beam with a mean energy of 1.3 GeV directed at the Super-Kamiokande detector. We observed the energy-dependent disappearance of nu(mu), which we presume have oscillated to nu(tau). The probability that we would observe these results if there is no neutrino oscillation is 0.0050% (4.0 sigma). 相似文献
134.
135.
Three kinds of europium β-diketonates Eu(DBM)3, Eu(BA)3 and Eu(TTA)3 (DBM: Dibenzoylmethane; BA: 1-Benzoylacetone; TTA: Thenoyltrifluoroacetone) were doped in poly(methyl methacrylate) (PMMA) matrix. The doped systems were studied by using photoluminescent (PL) spectroscopy, emission decay experiments and X-ray diffractometry. Eu(III) ions in the doped Eu(DBM)3/PMMA systems have two distinct symmetric sites and the emission band changes greatly with the compositions. Eu(III) in the Eu(BA)3/PMMA systems gives only one symmetric site in the doped systems and the emission band changes slightly with the compositions. Although two distinct symmetric sites of Eu(III) can be distinguished in the doped systems of Eu(TTA)3/PMMA, the two sites have similar 5D0 lifetimes and the luminescent spectra almost do not change with the compositions. XRD reveals that crystallites were formed in the doped Eu(DBM)3/PMMA systems that have different crystalline structure from that of the chelate, and Eu(BA)3 and Eu(TTA)3 exist in amorphous state in the doped systems. The difference between the PL properties and structures of the doped systems for the three kinds of chelates should be attributed to different interactions between the chelate molecules and between the chelate and PMMA. 相似文献
136.
J.S.?Bae Y.H.?Kim J.K.?Jang K.S.?Shim J.K.?Lee J.H.?JeongEmail author S.S.?Yi H.L.?Park 《Applied Physics A: Materials Science & Processing》2004,78(7):1073-1077
Mn-doped ZnGa2O4-xSx thin-film phosphors have been grown using a pulsed laser deposition technique at varying growth conditions. Structural characterization was carried out on a series of ZnGa2O4-xSx:Mn2+ films grown on MgO(100) substrates using Zn-rich ceramic targets. Oxygen pressure was fixed at 100 mTorr and substrate temperatures were varied from 500 to 700 °C. The results of X-ray-diffraction patterns showed that the lattice constants of the ZnGa2O3.95S0.05:Mn2+ thin films decrease with the substitution of sulfur for the oxygen in ZnGa2O4. Measurements of photoluminescence (PL) properties of ZnGa2O4-xSx:Mn2+ thin films have indicated that MgO(100) is one of the most promising substrates for the growth of high-quality ZnGa2O4-xSx:Mn2+ thin films. In particular, the incorporation of sulfur into the ZnGa2O4 lattice could induce a remarkable increase of PL. The highest green-emission intensity was observed with ZnGa2O3.95S0.05:Mn2+ films, whose brightness was increased by a factor of 3.5 in comparison with that of ZnGa2O4:Mn2+ films. This phosphor may be promising for application to flat-panel displays. PACS 78.20.-e; 78.55.-m; 78.66.-w 相似文献
137.
Itaka K Kanayama N Nishiyama N Jang WD Yamasaki Y Nakamura K Kawaguchi H Kataoka K 《Journal of the American Chemical Society》2004,126(42):13612-13613
An siRNA nanocarrier formed through self-assembly of PEG-based block catiomer possessing two distinct amino groups with different pKa values in a side chain was developed. This design provided the carrier with a sufficient siRNA complexation and an assumed buffering capacity in the endosomes, allowing it to exhibit remarkable gene knockdown abilities as well as sufficient serum tolerability. 相似文献
138.
Drutskoy A Abe K Abe K Abe T Aihara H Akatsu M Asano Y Aulchenko V Aushev T Bakich AM Ban Y Bay A Bedny I Behera PK Bizjak I Bondar A Bozek A Bracko M Browder TE Casey BC Chao Y Cheon BG Chistov R Choi Y Chuvikov A Danilov M Dash M Dong LY Eidelman S Eiges V Gabyshev N Garmash A Gershon T Golob B Haba J Hagner C Handa F Hastings NC Hayashii H Hazumi M Hinz L Hokuue T Hoshi Y Hou WS Huang HC Igarashi Y Iijima T Inami K Ishikawa A Itoh R Iwasaki H Iwasaki M Iwasaki Y Jang HK Kang JH Kang JS 《Physical review letters》2004,92(5):051801
The radiative decay B-->phi K gamma is observed for the first time. The branching fraction for the charged B--->phi K- gamma decay mode is measured to be B(B--->phi K- gamma)=(3.4+/-0.9+/-0.4)x10(-6). The photon energy distribution for the B--->phi K- gamma decay is presented. The signal for the neutral B(0)-->phi K(0)gamma decay mode is not statistically significant and an upper limit, B(B(0)-->phi K(0)gamma)<8.3x10(-6) at 90% C.L., is set. The analysis is based on a data set of 90 fb(-1) collected by the Belle experiment at the e(+)e(-) asymmetric collider KEKB. 相似文献
139.
We present the effects of a finite number of pixels in elemental images on the resolution and the depth of focus in three-dimensional integral imaging (II). We show that the number of pixels in elemental images determines not only the lateral resolution but also the depth resolution. The minimum number of pixels required in each elemental image is calculated to avoid depth-of-focus degradation. We evaluate how II system performance degrades as the number of pixels in each elemental image changes. The product of the depth of focus and the lateral resolution squared is used as the performance metric. 相似文献
140.