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101.
M. Kumar G. Chourasiya R. K. Kher B. C. Bhatt C. M. Sunta 《Indian Journal of Physics》2011,85(4):527-550
Localized transitions, which represent sub-conduction recombination, have been investigated comprehensively using localized
recombination model (LRM) of thermally stimulated luminescence (TSL). The study reveals the following results:
(i) |
The conventional quasi-equilibrium (QE) approximation criteria do not hold in LRM and new criteria for QE approximation is
proposed. 相似文献
102.
Ashish Tiwari S. A. Khan R. S. Kher S. J. Dhoble 《Journal of Applied Spectroscopy》2011,78(5):680-685
ZnS:Cu nanocrystals capped with different capping molecules have been successfully synthesized by a simple aqueous method.
The prepared nanocrystals were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive
analysis by X-rays (EDAX). The surface characterization of the nanocrystals was done by FTIR spectroscopy. The effect of capping
agents on absorption and photoluminescence (PL) spectra of the ZnS:Cu nanocrystals was studied. A blue shift of the absorption
peaks was observed and attributed to a quantum confinement effect, which increases the band gap energy. The photoluminescence
spectra of the capped ZnS:Cu nanocrystals showed a broad peak in the range of 460–480 nm. The intensity of the PL spectra
strongly depended on the capping agents. 相似文献
103.
Poulami Ghosh Ashwini Kumar Sharma 《Applied Physics A: Materials Science & Processing》2014,115(1):235-244
We report on the growth of zinc oxide diamond-shaped nanostructured thin films by pulsed laser deposition technique on silicon substrate at different substrate temperatures (room temperature to 600 $^{\circ }$ C) and at fixed background pressure of oxygen using Nd:YAG laser at a wavelength of 532 nm. The influence of substrate temperature on the grain size, surface morphology and optical properties is characterized by x-ray diffraction, field-emission scanning electron microscope, photoluminescence and Raman spectroscopy. x-ray diffraction results show that the grain size increases with increasing substrate temperature during the growth of ZnO thin films due to improved crystallinity but at 450 $^{\circ }$ C the crystallinity degrades. It is attributed to the formation of diamond-shaped ZnO nanostructures as supported by the field emission scanning electron microscope images. Consequently, increase in photoluminescence and Raman intensities is also attributed to the formation of diamond-shaped structures. The growth of diamond-shaped structure is discussed in the light of growth of various planes in the hexagonal structure of ZnO. 相似文献
104.
Limi Goswami Pranjal Gogoi Junali Gogoi Ashwini Borah Manash R. Das Romesh C. Boruah 《Tetrahedron letters》2014
A mild and selective protocol has been developed for the palladium-catalyzed phosphine-free Suzuki cross-coupling reaction of aryl bromides with arylboronic acids in aqueous tea extract at room temperature. It is noteworthy that the aqueous tea extract plays an important role in the reaction, and various functional groups are tolerated under the optimized conditions. The reactions proceeded with very good chemoselectivity in favor of the bromo instead of the chloro group even at higher temperatures. Furthermore, this protocol could be applied to the cross-coupling of 4-bromoindole without protecting the base sensitive amine group with arylboronic acids in moderate to excellent yields. 相似文献
105.
106.
Gamma ray induced sensitization in CaSO4 :Dy has been compared for different temperatures during irradiation (25° 120° and 250°C). Enhanced sensitization at elevated temperatures seems to support the competing trap model for supralinearity and sensitization in CaSO4 :Dy. 相似文献
107.
108.
109.
Ashwini A. Ghogare Imran Rizvi Tayyaba Hasan Alexander Greer 《Photochemistry and photobiology》2014,90(5):1119-1125
We describe a pointsource sensitizer‐tipped microoptic device for the eradication of glioma U87 cells. The device has a mesoporous fluorinated silica tip which emits singlet oxygen molecules and small quantities of pheophorbide sensitizer for additional production of singlet oxygen in the immediate vicinity. The results show that the device surges in sensitizer release and photokilling with higher rates about midway through the reaction. This was attributed to a self‐amplified autocatalytic reaction where released sensitizer in the extracellular matrix provides positive feedback to assist in the release of additional sensitizer. The photokilling of the glioma cells was analyzed by global toxicity and live/dead assays, where a killing radius around the tip with ~0.3 mm precision was achieved. The implication of these results for a new PDT tool of hard‐to‐resect tumors, e.g. in the brain, is discussed. 相似文献
110.
Dambarudhar Parida Manjeet Jassal Ashwini K. Agarwal 《Plasma Chemistry and Plasma Processing》2012,32(6):1259-1274
Cotton fabric was treated using styrene/helium glow plasma at the atmospheric pressure. After the treatment, the substrate was found to turn into a highly hydrophobic material showing water drop disappearance time of 60?min and water contact angle of 133°. The treatment was found to be durable even after vigorous washing. The effect of various parameters, such as discharge voltage and frequency, on fragmentation of styrene inside plasma zone was investigated using optical emission spectroscopy and GC?CMS. The types of fragments formed in the plasma zone were correlated with the hydrophobicity of the substrate. The chemical nature of surface of the substrate was analyzed using SEM and Raman spectroscopy to elucidate the possible mechanism of plasma modification. 相似文献
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