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51.
Abstract The interaction of iodine with donor bases such as neutral red (NR) and 1, 10 -phenanthroline (Ph) have been studied spectrophotometrically in C2H5OH. The results indicate the formation of 2:3 charge transfer complexes of the type (base)23I2. Mass, Raman and 1H NMR spectra have been recorded for each complex. I3 ? and I2 species are observed in these complexes. In addition, the d.c. conductivity is measured in the range (300–400) K°. The energy gap of the ionic conduction has been calculated. The conduction process is thought to involve iodide transfer between polyanions. 相似文献
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Many nitrated polycyclic aromatic hydrocarbons (NPAH) that are present in low concentrations in the environment and in emission
sources have been shown to be mutagenic and/or carcinogenic. This paper reviews the current methods of analysis of these compounds
with the emphasis on NPAH measurements in ambient particulate matter samples. 相似文献
54.
In this article, we study the C4- and D4-modules in terms of perspective direct summands, providing new characterizations and results. Endomorphism rings of C4-modules and extensions of right C4-rings are also investigated. Decompositions of C4-modules with restricted ACC on direct summands and D4-modules with restricted DCC on direct summands are obtained. 相似文献
55.
W. A. W. Razali K. Azman S. Hashim Yasser Saleh Mustafa Alajerami S. A. Syamsyir A. Mardhiah M. H. J. Ridzwan 《Optics and Spectroscopy》2013,115(5):701-707
A series of borate glass of the system xNd2O3-5MgO-20ZnO-(75 ? x)B2O3, where x = 0.5, 1.0,1.5, 2.0, and 2.5 was successfully fabricated using melt quench method. The properties of the glass were characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR), absorption and luminescence spectra. The upconversion properties of Nd3+ doped borate glass were observed by using 574 nm excitation wavelength corresponding to 4 I 15/2 → 2 H 114/2 transition. The emission bands centered at 460, 500 and 620 nm which corresponding to the Nd3+ transitions, 4 F 7/2 → 4 I 15/2, 2 H 11/2 → 4 I 15/2, and 4 F 9/2 → 4 I 15/2 respectively were observed at room temperature. The presence of Nd3+ in borate based glass could intensify the upconversion luminescence spectra as it can potentially be used as host materials for upconversion lasers. 相似文献
56.
El Sayed Moustafa Yasser B. Saddeek Essam R. Shaaban 《Journal of Physics and Chemistry of Solids》2008,69(9):2281-2287
Glasses with compositions 25Li2O-(75−x)Bi2O3-x B2O3, with 0?x?30 mol%, have been prepared using the melt quenching technique. The density and the molar volume have been determined. IR spectroscopy is used as a structural probe of the nearest neighbor environment in the glass network. The optical transmittance and reflectance spectrum of the glasses have been recorded in the wavelength range 400-1100 nm. The values of the optical band gap Egopt for indirect transition and refractive index have been determined for 0?x?30 mol%. The average electronic polarizability of the oxide ion αo2− and the optical basicity have been estimated from the calculated values of the refractive indices. Variations in the different physical parameters such as the density, molar volume, optical band gap, refractive index, average electronic polarizability of the oxide ion and optical basicity with B2O3 content have been analyzed and discussed in terms of the changes in the glass structure. 相似文献
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In this work, we study the hydration phenomenon on a molecular level in the gas phase where a selected number of water molecules can interact with the organic ion of interest. The stepwise binding energies (DeltaH degrees (n-1,n)) of 1-7 water molecules to the phenyl acetylene cation are determined by equilibrium measurements using an ion mobility drift cell. The stepwise hydration energies DeltaH degrees (n-1,n) are nearly constant at 39.7 +/- 6.3 kJ mol(-1) from n = 1 to 7. The entropy change is larger in the n = 7 step, suggesting cyclic or cage-like water structures. No water addition is observed on the ionized phenyl acetylene trimer consistent with cyclization of the trimer ion to form triphenyl benzene cations C(24)H(18) (+) which are expected to interact weakly with the water molecules due to steric interactions and the delocalization of the charge on the large organic ion. The work demonstrates that hydration studies of organic ions can provide structural information on the organic ions. 相似文献