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111.
Zafar A. Siddiqi M. Shahid Mohd Khalid Shabana Noor Sarvendra Kumar 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2010,75(1):61-68
The newly prepared homo-bimetallic complexes [M2(imda)2(H2O)4], [M2(imda)2(Bipy)2] (M = Co, Ni or Cu) and [Fe2(imda)2(H2O)3Cl] (H2imda = iminodiacetic acid and Bipy = 2,2′-bipyridine) have been studied employing IR, FAB-mass, 1H and 13C NMR, EPR and ligand field spectra, which indicated a high-spin state of metal ion with hexa-coordinate environment. 57Fe Mössbauer data of the homo-bimetallic complex [Fe2(imda)2(H2O)3Cl] confirm a high-spin configuration with Fe (±3/2 → 1/2) nuclear transitions and the presence of Kramer's double degeneracy. At RT, the spin–spin interactions of the neighbouring nuclei (Fe3+–Fe3+ = S5/2–S5/2) are anti-ferromagnetically coupled. However, at LNT, the complex acquires a mixed-valent [FeIII–FeII] composition corroborated from the X-band EPR data. CV studies indicated the presence of quasi-reversible redox CuII/I, CuII/III, FeIII/II, FeIII/I and FeII/I couples. 相似文献
112.
Zafar A. Siddiqi Mohd Khalid Sarvendra Kumar M. Shahid Shabana Noor 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2010,75(2):841-845
Spectral and molecular model computations on homo-dinuclear complexes [M2L2(H2O)2Cl2] [L = 1-(salicylaldeneamino)-3-hydroxypropane, M = Cr3+, Mn3+, Fe3+, Co3+, Ni3+ or Cu3+] are consistent with a distorted hexa-coordinate geometry. X-band EPR spectral data indicated a rhombic distortion around Cu(II) ion. Magnetic moment and 57Fe Mössbauer data confirmed a high-spin state electronic configuration (t2g3eg2, S = 5/2) and asymmetric ligand environment around Fe(III) with nuclear transitions Fe(±3/2 → 1/2) exhibiting Kramer's double degeneracy. The neighboring Fe(III) nuclei in the homo-dinuclear species are antiferromagnetically coupled. 相似文献
113.
The nanocatalyst-assisted sonodegradation of Basic Blue 41 (BB41) dye in aqueous medium was modeled and optimized using response
surface method (RSM) based on Box-Behnken design. The studied variables included pH, initial dye concentration, H2O2 concentration and sonolysis time while each factor varied at three levels: Low level (−1), Medium level (0) and High level
(+1). The ultrasound -assisted degradation was well described by developing quadratic model with correlation value squared
(R2) of 0.9114. Factor effects along with interaction effects were evaluated. The graphical optimization step was conducted to
achieve the best experimental condition in dye removal. pH, H2O2 concentration and initial dye concentration of the reaction were investigated. It was recognized that at lower pH values
the dye removal rate decreased. However, dye removal rate increased (82.5%) by increasing the concentration of H2O2 and by lowering the initial dye concentration.
相似文献
114.
Hanaa A. El-Boraey Randa M. Abdel-Rahman Ensaf M. Atia Khalid H. Hilmy 《Central European Journal of Chemistry》2010,8(4):820-833
Two novel Schiff base ligands of 2-amino-3-cyano-1,5-diphenylpyrrole and salicylaldehyde (HL1) or 2- hydroxy1-naphthylaldehyde (HL2) and their copper(II) complexes have been synthesized and characterized by elemental analyses, spectral (UV-Vis, IR, EPR,
Mass (for ligands)), thermal (DTA-TGA) methods, magnetic and conductance measurements. IR results demonstrate the bidentate
binding of the Schiff base ligands involving azomethine nitrogen, phenolic or naphtholic oxygen and suggest the presence of
HL2 and complexes (1, 2, 4 and 8) in enolimine-ketonamine tautomeric forms in the solid state. The EPR spectral data of complexes
(2, 5, 6) show that the metal — ligand bonds have considerable covalent character. The thermal studies show that complexes
(1, 2, 4 and 8) that are present in enolimine-ketonamine tautomeric forms exhibit lower thermal stability. The effect of synthesized
ligands (HL1, HL2) and complexes (1, 5) were tested on the mortality of entomopathogenic nematodes (EPN) (Heterorhabditis bacteriophora and
Steinernema carpocapsae). The study shows that the mortality of the nematodes increased with increasing concentrations of
copper(II) ion, ligands and complexes. Copper(II) ion was the most toxic for EPN.
相似文献
115.
M. Khalid A.F. Ismail C.T. Ratnam Y. Faridah W. Rashmi M.F. Al Khatib 《Radiation Physics and Chemistry》2010,79(12):1279-1285
Effect of radiation dose and carbon nanotubes (CNT) on the mechanical properties of standard Malaysian rubber (SMR) was investigated in this study. SMR nanocomposites containing 1–7 phr CNT were prepared using the solvent casting method and the nanocomposites were radiated at doses of 50–200 kGy. The change in mechanical properties, especially, tensile strength (Ts), elongation at break (Eb), hardness and tensile modulus at 100% elongation (M100) were studied as a function of radiation dose. The structure and morphology of reinforced natural rubber was investigated by FESEM, TEM and AFM in order to gain further evidence on the radiation-induced crosslinking. It was found that the Ts, M100 and the hardness of the SMR/CNT nanocomposites significantly increased with radiation dose; the elongation at break exhibited an increase up to 100 kGy, and a downward trend thereafter. Results on gel fraction further confirmed the crosslinking of SMR/CNT nanocomposites upon radiation. 相似文献
116.
Anti-reflection coatings of solar cells have been fabricated using different techniques. The techniques used include SiO2 thermal oxidation, ZnO/TiO2 sputtering deposition and porous silicon prepared by electrochemical etching. Surface morphology and structural properties of solar cells were investigated by using scanning electron microscopy and atomic forces microscopy. Optical reflectance was obtained by using optical reflectometer. I-V characterizations were studied under 80 mW/cm2 illumination conditions. Porous silicon was found to be an excellent anti-reflection coating against incident light when it is compared with another anti-reflection coating and exhibited good light-trapping of a wide wavelength spectrum which produced high efficiency solar cells. 相似文献
117.
Parvin Farshchi Seyed Khatiboleslam Sadrnezhaad Naser Moharram Nejad Mahmood Mahmoodi Leila Ibrahimi Ghavam Abadi 《Journal of nanoparticle research》2011,13(8):3511-3519
Using survey data, public awareness of and attitudes toward nanotechnology are examined in Iran (N = 759). Iran is a developing country with a national nanotechnology action plan for a ten year period starting from 2003
and has been active in the field of research and development of nanotechnology meanwhile. First, the results show that majority
of people are still not familiar with nanotechnology and perceived risks posed by this technology are not considered to be
a lot and most people feel its benefits outweigh the risks. The emotions toward this technology are of a hopeful and positive
nature and this technology is looked upon favorably in Iran. In particular, our results reveals that although the level of
trust is high specially in scientists to communicate the risks with the public, there are a great number who just have some
trust not quite a lot of it. Knowing that it is a hard and time-consuming effort to manage a nation’s view on nanotechnology,
extensive research as well as collaboration with other countries is needed to effectively communicate the risks in time. 相似文献
118.
Asma Rehman Muhammad Irfan Majeed Ayesha Ihsan Syed Zajif Hussain Saif-ur-Rehman Muhammad Afzal Ghauri Zafar M. Khalid Irshad Hussain 《Journal of nanoparticle research》2011,13(12):6747-6754
Abstract
A simple and environmentally benign green method is reported to decorate growing fungal hyphae with high loading of gold nanoparticles, which were initially produced using aqueous tea extract as a sole reducing/stabilizing agent. Inoculation of fungal spores in aqueous suspension of nanoparticles led to the growth of intensely red-coloured fungal hyphae due to the accumulation of gold nanoparticles. Heat treatment of these hybrid materials led to the formation of porous gold microwires. This report is thus an interesting example of using green and sustainable approach to produce nanostructured materials which have potential applications in catalysis, sensing and electronics. 相似文献119.
Khalid Mujasam Batoo 《Physica B: Condensed Matter》2011,406(3):382-387
The paper reports on the effect of Al substitution on the structural and electrical properties of bulk ferrite series of basic composition MnFe2−2xAl2xO4 (0.0≤x≤0.5) synthesized using solid state reaction method. XRD analysis confirms that all the samples exhibit single phase cubic spinel structure excluding presence of any secondary phase. The dielectric constant shows a normal behaviour with frequency, whereas the loss tangent exhibits an anomalous behaviour with frequency for all compositions. Variation of dielectric properties and ac conductivity with frequency reveals that the dispersion is due to Maxwell-Wagner type of interfacial polarization in general and hopping of charge between Fe+2 and Fe+3 as well as between Mn+2 and Mn+3 ions at octahedral sites. The complex impedance plane spectra shows the presence of two semicircles up to x=0.2, and only one semicircle for the higher values of x. The analysis of the data shows that the resistive and capacitive properties of the Mn ferrite are mainly due to processes associated with grain and grain boundaries. 相似文献
120.
Metamaterial absorbers have attracted considerable attention for applications in the terahertz range. In this Letter, we report the design, fabrication, and characterization of a terahertz dual band metamaterial absorber that shows two distinct absorption peaks with high absorption. By manipulating the periodic patterned structures as well as the dielectric layer thickness of the metal-dielectric-metal structure, significantly high absorption can be obtained at specific resonance frequencies. Finite-difference time-domain modeling is used to design the structure of the absorber. The fabricated devices have been characterized using a Fourier transform IR spectrometer. The experimental results show two distinct absorption peaks at 2.7 and 5.2?THz, which are in good agreement with the simulation. The absorption magnitudes at 2.7 and 5.2?THz are 0.68 and 0.74, respectively. 相似文献