排序方式: 共有17条查询结果,搜索用时 140 毫秒
11.
Koji Iijima Masako Goto Shogo Enomoto Hideyuki Kunugita Kazuhiro Ema Masanori Tsukamoto Noriya Ichikawa Hiroshi Sakama 《Journal of luminescence》2008,128(5-6):911-913
This paper presents an investigation into the relaxation process of photo-excited carriers in anatase TiO2 thin films, in which the concentration of oxygen vacancy is controlled by annealing at various temperatures in an oxygen atmosphere. The influence of oxygen vacancies on absorption spectra, photoluminescence (PL) spectra, and PL decay dynamics are discussed. 相似文献
12.
Oda M Hasegawa A Iwami N Nishiura K Ando N Nishiyama A Horiuchi H Tani T 《Colloids and surfaces. B, Biointerfaces》2007,56(1-2):241-Optics
Photobrightening and photobluing effects of photoluminescence (PL) from CdSe/ZnS/TOPO nanocrystal ensembles, i.e. ca. 1000 nanocrystals, have been investigated in several environments. The PL intensity increases more than twice with blue shift under continuous light irradiation in a wet nitrogen (H2O/N2) atmosphere, while in a pure nitrogen atmosphere and vacuum their behaviors are nothing particular. In addition, increasing rates of both the brightening and bluing effects in the H2O/N2 atmosphere depend on irradiation intensities. These results suggest that both effects should be associated with photo-adsorption of water molecules onto nanocrystal surfaces. As for the brightening effect, we propose that the photo-adsorption of water molecules provides some restoring functions to PL-quenching defects or trap-sites on or near nanocrystal surfaces. On the other hand, the origin of the bluing effect is not clear from the results of the ensemble measurements. To get further insight into the bluing effect, PL spectra from single nanocrystals are measured under continuous light irradiation in cyclic environments in which the H2O/N2 atmosphere and vacuum are alternating. As a result, blue-shifted PL induced by the light irradiation in the H2O/N2 atmosphere recovers almost to its initial one reversibly under evacuation. The mechanism of the photobluing effect will be discussed also on the bases of the photobrightening model introduced above. 相似文献
13.
Shin Horiuchi Takeshi Hanada Noriya Izu Ichiro Matsubara 《Journal of nanoparticle research》2012,14(3):734
The microstructures and the organization mechanism of cerium oxide (ceria) nanospheres were investigated by transmission electron
microscopy. The ceria nanospheres with the diameter of 50–150 nm were produced by the polyol synthesis method with cerium
nitrate precursor and with polyvinylpyrrolidone (PVP) used as a protecting agent. Dose-limited observations performed by energy-filtering
transmission electron microscopy revealed that the ceria nanospheres were the aggregated products consisting of ceria nanocrystallites
~3 nm in size and PVP-derived polymer products. It was found that the ceria nanocrystallites were oriented within the nanospheres
by high-resolution transmission electron microscopy and selected-area electron diffraction. Selective adsorption of PVP on
the crystal facets of the ceria nanocrystallites was suggested, and the aggregation of the PVP-adsorbed ceria through cross-linking
reaction of PVP causes the crystal orientation. 相似文献
14.
Ichikawa N Iwanowska M Kawai M Calers C Paulus W Shimakawa Y 《Dalton transactions (Cambridge, England : 2003)》2012,41(35):10507-10510
Brownmillerite SrCoO(2.5) (010) thin films synthesized by pulsed laser deposition became amorphous when reduced at low temperatures by CaH(2), indicating that the infinite-layer structure with the square planar Co(2+)O(4) configuration is unstable. Ferromagnetic and conducting perovskite SrCoO(3) epitaxial thin films, on the other hand, were obtained topotactically at room temperature by oxidation with NaClO. 相似文献
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16.
Kawaguchi M Sakui N Okanouchi N Ito R Saito K Nakazawa H 《Journal of chromatography. A》2005,1062(1):23-29
A novel method called thermal desorption (TD) with in tube silylation followed by gas chromatography-mass spectrometry (GC-MS), which is used for the determination of trace amounts of alkylphenols (APs) in river water samples, is described. APs are extracted from river water samples and concentrated by the stir bar sorptive extraction (SBSE) technique. The stir bar coated with polydimethylsiloxane (PDMS) is added to 2.0 ml water sample and stirring is carried out for 60 min at room temperature (25 degrees C) in the vial. Then, the PDMS stir bar is subjected to TD with in tube silylation followed by GC-MS. The detection limit is of the sub pg ml(-1) (ppt) level. The method shows good linearity and the correlation coefficients are higher than 0.99 for all analytes. The average recoveries of APs are higher than 90% (R.S.D.: 3.6-14.8%, n=6). This simple and sensitive analytical method may be used in the determination of trace amounts of APs in river water samples. 相似文献
17.
Hiromi Horiuchi Noriya Iwami Akashi Ohtaki Tamotsu Zako Masafumi Yohda Toshiro Tani 《Journal of luminescence》2007,127(1):192-197
Feasibilities to stabilize CdSe/ZnS/trioctylphosphineoxide (TOPO) nanocrystals (quantum dots, QDs) in aqueous solutions with prefoldin macromolecules in their bioactive states are reported. Prefoldin is a jellyfish-shaped hexameric co-chaperone of the group II chaperonins. As a protein folding intermediate is captured within its central cavity, so CdSe/ZnS/TOPO QDs would also be included within this cavity. It is also found the QDs can be much more dispersed in aqueous solutions and suspended for certain period of time by adding trace amount of t-butanol in the buffer prior to the mixing of the QDs mother solution. While biochemical procedures are evaluated with ordinary fluorescence measurements, possible complex formations are also evaluated with TIRFM single-molecule detection techniques. 相似文献