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101.
Inaguma Y Muronoi T Sano K Tsuchiya T Mori Y Katsumata T Mori D 《Inorganic chemistry》2011,50(12):5389-5395
We synthesized polycrystalline pristine and Pr(3+)-doped perovskites La(1/3)MO(3) (M = Nb, Ta):Pr(3+) and investigated their crystal structure, optical absorption, and luminescence properties. The optical band gap of La(1/3)NbO(3) (3.2 eV) is smaller than that of La(1/3)TaO(3) (3.9 eV), which is primarily due to the difference in electronegativity between Nb and Ta. In La(1/3)NbO(3):Pr(3+), the red emission assigned to the f-f transition of Pr(3+) from the excited (1)D(2) level to the ground (3)H(4) state upon band gap photoexcitation (near-UV) was observed, whereas the f-f transition of Pr(3+) with blue-green emission from the excited (3)P(0) level to the ground (3)H(4) state was quenched. On the other hand, in La(1/3)TaO(3):Pr(3+), the blue-green emission upon band gap photoexcitation was observed. Their differences in emission behavior are attributed to the energy level of the ground and excited states of 4f(2) for Pr(3+), relative to the energy levels of the conduction and valence bands, and the trapped electron state, which mediates the relaxation of electron from the conduction band to the excited state of Pr(3+). La(1/3)NbO(3):Pr(3+) is a candidate red phosphor utilizing near-UV LED chips (e.g., λ = 375 nm) as an excitation source. 相似文献
102.
Katsumata K Ohno Y Tomita K Sakai M Nakajima A Kakihana M Fujishima A Matsushita N Okada K 《Photochemistry and photobiology》2011,87(5):988-994
Titanium dioxide thin films were prepared by using four water-soluble titanium complexes of titanium-lactate, tartalate, malate and salicylate complex solutions. The crystalline phases detected in the films were anatase. The surface microstructures of the four film samples were different in their grain sizes. Photocatalytic decomposition activity of the four films was almost the same, but their photoinduced hydrophilicities were different. The film prepared using titanium-salicylate complex exhibited lower hydrophilic conversion rate than the other films. Grain size and stress yielded to the film are considered to be important factors on the photoinduced hydrophilicity. 相似文献
103.
Md. Nurul Amin Satoshi Kaneco Yukitake Nakano Hideyuki Katsumata Tohru Suzuki Kiyohisa Ohta 《Mikrochimica acta》2008,161(1-2):73-79
A multi-pumping flow system for the spectrophotometric determination of nitrite and nitrate is described. The determination
of nitrite is based on the Griess-Ilosvay reaction. Nitrate can be determined after its on-line reduction to nitrite using
hydrazine sulphate in alkaline medium. Calibration was linear up to 3 mg NO2
− L−1 with a limit of detection (3sb/S) of 0.013 mg NO2
− L−1 an injection throughput of 55 injections h−1 and a repeatability (RSD) of 0.5% for the direct determination of nitrite. Two calibration graphs within the ranges 0.039–7 mg
NO3
− L−1 and 0.026–5 mg NO2
− L−1 were run for the determination of nitrate and nitrite under reducing conditions, respectively. A limit of detection of 0.039 mg
NO3
− L−1 was obtained. An injection throughput of 27 injections h−1 and an RSD lower than 1.5% were achieved. The method was successfully applied to the determination of nitrite and nitrate
in water samples.
Correspondence: Víctor Cerdà, Department of Chemistry, University of the Balearic Islands, Carretera de Valldemossa Km7.5,
07122 Palma de Mallorca, Spain 相似文献
104.
Katsumata M Takeuchi A Kazumura K Koike T 《Journal of photochemistry and photobiology. B, Biology》2008,90(3):152-162
A new method for measuring delayed luminescence (delayed fluorescence) employs preillumination and a dark waiting period before normal excitation. The preillumination results in a concavity and a convexity in the decay curve in delayed luminescence in the green alga Pseudokirchneriella subcapitata. Formation of the concavity and the convexity is not affected by excitation wavelength (680 nm and 700 nm). However, the concavity and the convexity progressively decrease as the dark waiting period increases after preillumination. The formation of the concavity and the convexity was inhibited by exposure to the electron transport inhibitors DBMIB (644 μg/L, 2.0 μM) and Antimycin A (55 μg/L, 0.1 μM). Samples exposed to DBMIB exhibited noticeable reduction in the concavity, whereas samples exposed to Antimycin A exhibited pronounced reduction in the convexity. There is a possibility that the formation and disappearance of the concavity and the convexity are due to the reduction–oxidation state of the plastoquinone pool and the cyclic electron transport. We expect this method being useful in evaluating the effects of chemicals (particularly toxic chemicals) on photosynthetic reactions, and the method may also help to resolve questions regarding the source of long delayed luminescence. 相似文献
105.
Hideyuki Katsumata Hiroshi Kojima Satoshi Kaneco Tohru Suzuki Kiyohisa Ohta 《Microchemical Journal》2010,96(2):348-351
A sensitive and selective preconcentration method using solid-phase extraction (SPE) disk, namely multiwalled carbon nanotubes (MWCNTs) disk, is proposed for the determination of atrazine and simazine in water samples. Atrazine and simazine were extracted on MWCNTs disk and then determined by gas chromatography–mass spectrometry (GC/MS). Several parameters on the enrichment factor of the analytes were investigated. The experimental results showed that it was possible to obtain quantitative analysis when the solution pH was 5 using 200 mL of validation solution containing 0.1 μg of triazines and 5 mL of acetone as an eluent. The maximum enrichment factors for atrazine and simazine were 3900 ± 250 and 4000 ± 110, respectively when 200 mL of sample solution volume was used. Relative standard deviations for seven determinations were 6.9% (atrazine) and 3.0% (simazine) under optimum conditions. The linear range of calibration curves were 0.1 to 1 ng mL− 1 for each analyte with good correlation coefficients. The detection limits (3S/N) were 2.5 and 5.0 pg mL− 1 for atrazine and simazine, respectively. The proposed method was successfully applied to the determination of atrazine and simazine in environmental water samples with high precision and accuracy. 相似文献