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21.
Prof. Dr. Abdolali Alemi Prof. Dr. Axel Klein Gerd Meyer Mahboubeh Dolatyari Aliakbar Babalou 《无机化学与普通化学杂志》2011,637(1):87-93
New LnxBi2–xSe3 (Ln: Sm3+, Eu3+, Gd3+, Tb3+) based nanomaterials were synthesized by a co‐reduction method. Powder XRD patterns indicate that the LnxBi2–xSe3 crystals (Ln = Sm3+, Eu3+, x = 0.00–0.44 and Ln = Gd3+, Tb3+, x = 0.00–0.50) are isostructural with Bi2Se3. The cell parameter c decreases for Ln = Eu3+, Gd3+, Tb3+ upon increasing the dopant content (x), while a slightly increases. Changes in lattice parameters could be related to the radii of cations. SEM images show that doping of the lanthanide ions in the lattice of Bi2Se3 generally results in nanoflowers. For the terbium compound two kinds of morphologies (nanoflowers and nanobelts) were observed. UV/Vis absorption and emission spectroscopy reveals mainly electronic transitions of the Ln3+ ions. Emission spectra show intense transitions from the excited to the ground state of Ln3+ and energy transfer from the Bi2Se3 lattice. Emission spectra of europium‐doped materials, in addition to the characteristic red emission peaks of Eu3+, show an intense blue emission band centered at 432 nm, originating from the 4f65d1 to 4f7 configuration in Eu2+. EPR measurements confirm the existence of Eu2+ in the materials. Interestingly, for all samples starting at low Ln3+ concentration, the emission intensity rises to a maximum at a Ln3+ concentration of x = 0.2 and falls again steadily to a minimum at x = 0.45. 相似文献
22.
Abdolali Alemi Younes Hanifehpour Sang Woo Joo Aliakbar KhandarAli Morsali Bong-Ki Min 《Physica B: Condensed Matter》2012,407(1):38-43
New LnxSb2−xSe3 (Ln: Yb3+, Er3) based nanomaterials were synthesized by a co-reduction method. Powder XRD patterns indicate that the LnxSb2−xSe3crystals (Ln=Yb3+, Er3+, x=0.00-0.12) are isostructural with Sb2Se3. The cell parameters b and c decrease for Ln=Er3+ and Yb3+ upon increasing the dopant content (x), while a increases. SEM images show that doping of the lanthanide ions in the lattice of Sb2Se3 generally results in nanoflowers. UV-vis absorption and emission spectroscopy reveals mainly electronic transitions of the Ln3+ ions in case of Yb3+ doped nanomaterials. Emission spectra of doped materials, in addition to the characteristic red emission peaks of Sb2Se3, show additional emission bands centered at 955 nm, originating from the 2F7/2→2F5/2 transition (f-f transitions) of the Yb3+ ions. DSC curves indicate that Sb2Se3 has the highest thermal stability. The temperature dependence of the electrical resistivity of doped-Sb2Se3 with Yb3+ and Er3+ was studied. 相似文献
23.
Olav Vahtras Hans rgren Hans Jrgen AA. Jensen 《Journal of computational chemistry》1994,15(6):573-579
The evaluation of gradient vectors of a general operator with one-index, double-one-index, or higher-order one-index transformed integrals is a key operation in multiconfiguration response theory calculations. We describe an integral-driven direct algorithm that carries out this operation efficiently without pretransforming the integrals. The use of this algorithm leads to a considerable reduction in disk space and timing. © 1994 by John Wiley & Sons, Inc. 相似文献
24.
Yukio Hinatsu Yuki Izumiyama Abdolali Alemi Makoto Wakeshima Yukio Morii 《Journal of solid state chemistry》2004,177(1):38-44
Magnetic properties of double perovskite compounds Ba2HoRuO6 and Ba2HoIrO6 have been reported. Powder X-ray and neutron diffraction measurements show that these compounds have a cubic perovskite-type structure with the space group and the 1:1 ordered arrangement of Ho3+ and Ru5+ (or Ir5+) over the 6-coordinate B sites. Results of the magnetic susceptibility and specific heat measurements show that Ba2HoRuO6 exhibits two magnetic anomalies at 22 and 50 K. Analysis of the temperature dependence of magnetic specific heat indicates that the anomaly at 50 K is due to the antiferromagnetic ordering of Ru5+ ions and that the anomaly at 22 K is ascribable to the magnetic interaction between Ho3+ ions. Neutron diffraction data collected at 10 and 35 K show that the Ba2HoRuO6 has a long range antiferromagnetic ordering involving both Ho3+ and Ru5+ ions. Each of their magnetic moments orders in a Type I arrangement and these magnetic moments are anti-parallel in the ab-plane with each other. The magnetic moments are aligned along the c-direction. On the other hand, Ba2HoIrO6 is paramagnetic down to 1.8 K. 相似文献
25.
A new series of 6,8-dibromo-2-(4-chlorophenyl)quinazolin-4(3H)-one derivatives VI–XIII were synthesized. Their chemical structures were confirmed by spectral and elemental analysis. The cytotoxic effect of the newly synthesized compounds was tested in vitro against human breast cancer cell line (MCF-7). Most of the tested compounds have shown promising cytotoxic activity. Compounds X and XIIIb exerted a powerful cytotoxic effect against MCF-7 with a very low IC50 (0.0015 and 0.0047 µmol/ml), while compounds VI, VII, VIII, XIIb, XI, XIIIc and IX exerted a moderate cytotoxic effect (IC50 0.01523, 0.0213, 0.031, 0.0478, 0.049, 0.068 and 0.079 µmol/ml respectively), compared to doxorubicin (0.0025 µmol/ml). Exploring their apoptotic effect; interestingly,all compounds activated apoptotic cascade in MCF-7. Compounds VI, XIIIb, XIIb, XI, XIIa, VII, V and VIII showed potent effect even much more than doxorubicin by 12.87–5.91 folds, while compounds XIIIc, IX, XIIIa, XIIc and X showed moderate increase in CASP3 activity by 4.96–3.22 folds relative to untreated cells more or less similar to doxorubicin (5.57 folds). 相似文献
26.
Obliquely propagating altra-low-frequency dust-electromagnetic waves in a self-gravitating, warm, magnetized, two fluid dusty
plasma system have been investigated. Two special cases, namely, dust-Alfvén mode propagating parallel to the external magnetic
field and dustmagnetosonic mode propagating perpendicular to the external magnetic field have also been considered. It has
been shown that effects of self-gravitational field, dust fluid temperature, and obliqueness significantly modify the dispersion
properties of these ultra-low-frequency dust-electromagnetic modes. It is also found that in parallel propagating dust-Alfvén
mode these effects play no role, but in obliquely propagating dust-Alfvén mode or perpendicular propagating dust-magnetosonic
mode the effect of self-gravitational field plays destabilizing role whereas the effect of dust/ion fluid temperature plays
stabilizing role. 相似文献
27.
It is shown how one can transform scalar first-order ordinarydifferential equations which admit non-local symmetries of theexponential type to integrable equations admitting canonicalexponential non-local symmetries. As examples we invoke theAbel equation of the second kind, the Riccati equation and naturalgeneralizations of these. Moreover, our method describes howa double reduction of order for a second-order ordinary differentialequation which admits a two-dimensional Lie algebra of generatorsof point symmetries can be affected if the second-order equationis first reduced in order once by a symmetry which does notspan an ideal of the two-dimensional Lie algebra. 相似文献
28.
29.
Abdolali Alemi Younes Hanifehpour Sang Woo Joo Aliakbar KhandarAli Morsali Bong-Ki Min 《Physica B: Condensed Matter》2011,406(14):2801-2806
New LnxSb2−xS3 (Ln: Lu3+, Ho3+, Nd3+)-based nanomaterials were synthesized by a co-reduction method. Powder XRD patterns indicate that the LnxSb2−xS3 crystals (Ln=Lu3+, Ho3+, x=0.00−0.1 and Ln=Nd3+, x=0.00−0.08) are isostructural with Sb2S3. SEM images show that doping of Lu3+ and Ho3+ ions in the lattice of Sb2S3 results in nanorods while that in Nd3+ leads to nanoflowers. UV-vis absorption and emission spectroscopy reveal mainly electronic transitions of the Ln3+ ions in case of Ho3+ and Nd3+ doped nanomaterials. Emission spectra show intense transitions from excited to ground state of Ln3+. Emission spectra of doped materials, in addition to the characteristic red emission peaks of Sb2S3, show other emission bands originating from f-f transitions of the Ho3+ ions. TGA curves indicated that Sb2S3 has the highest thermal stability. The electrical conductance of Ln-doped Sb2S3 is higher than undoped Sb2S3, and increase with temperature. 相似文献
30.
In this research, we report on the characterization of La1?xTbxMn0.9Zn0.1O3+d (LTMZ) (0.0≤x≤0.32). Nanoparticles with high surface area were synthesized by the polymerized complex method based on the Pechini-type reaction. High-quality nanopowders with controlled stochiometry and microstructure were prepared in the temperature range of 700–800 °C for 6 h, with mean particle sizes of approximately 18.35 nm. The synthesized materials were characterized by X-ray powder diffraction, fourier transform infrared spectrometry and photoluminescence (PL). PL measurements showed the characteristic green emission of Tb3+ ions in crystalline LTMZ powders due to the 5D 4→7F J transitions of the 4f electrons of Tb3+ ions. The structure, homogeneity and particle size of the obtained compounds during different stages were investigated by scanning electron microscopy. 相似文献