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151.
The classic silver diethyldithiocarbamate (SDDC) spectrophotometric procedure for arsenic determination has been used for investigation of the effect of cathodic electrolyte on the performance of electrochemical hydride generation (HG) from graphite cathode. The results of this study show that the presence of a soft metal ion such as Cd(II), Sn(II) and/or Zn(II) in the acidic cathodic electrolyte can increase effectively the efficiency of electrochemical hydride generation and decrease the effect of interferences. The possible mechanisms of these effects have been discussed in detail. The parameters related to the electrochemical hydride generation were investigated. Also the characteristic data of the electrochemical hydride generation and common hydride generation by NaBH4 were compared. Under optimised conditions, the system is selective to As(III) and total inorganic analyses can be performed after a pre-reduction stage prior to electrochemical hydride generation. This will allow the differential determination of inorganic arsenic species. The method is appropriate to the determination of 4-40 μg of each arsenic species. 相似文献
152.
Esmaeil Zaminpayma Payman Nayebi Kavoos Mirabbaszadeh 《Journal of Cluster Science》2008,19(4):623-629
The thin-film growth has been confirmed to be assembled by an enormous number of clusters in ICBD method. In sequence of clusters’
depositions proceeds to form the thin-film to understand quantitatively the interaction mechanisms between the cluster atoms
and the substrate atoms, we use molecular dynamics simulation with EAM potential. The quantitative of flatness of deposition
and percent of disordered atoms were proposed to evaluate the property of thin-film. In this simulation, three different Co
cluster sizes of 55, 70, and 100 atoms with different velocities (100 up to 800 m/s) were deposited on a Al(0 0 1) substrate
whose temperatures were set between 300 and 500 K. The simulations begin at specific equilibrium temperature of clusters and
the substrate. The simulations are performed at different temperatures of the clusters and substrate and for different sizes
of clusters. We showed that the percent of disordered atoms of substrate are affected by the cluster size and velocity of
the clusters. Temperature dependence of the number of disordered atoms for different cluster’s velocity was observed. We investigated
the effect of cluster size and initial velocity of cluster on the value of flatness. 相似文献
153.
Tahereh Soleymani Ahooie Najmedin Azizi Issa Yavari Mohammad Mahmoudi Hashemi 《Journal of the Iranian Chemical Society》2018,15(4):855-862
A green, reliable synthetic method and highly efficient one-pot three-component synthesis of 2,4,5-trisubstituted imidazoles from 1,2-diketones, aldehydes and ammonium acetate in the presence of recyclable magnetic graphitic carbon nitride nanocomposite (Fe3O4@g-C3N4) has been developed. Various imidazole derivatives were obtained in moderate to excellent yields and high purity after recrystallization from ethanol. Interestingly, the low-cost Fe3O4@g-C3N4 a nontoxic and inexpensive catalyst showed excellent recyclability using an external magnet without loss of parent catalytic activity even after ten cycles and its provides new opportunities for the truly environmental friendliness methodology. 相似文献
154.
Ahooie Tahereh Soleymani Azizi Najmedin Hashemi Mohammad Mahmoudi Yavari Issa 《Research on Chemical Intermediates》2018,44(2):1425-1436
Research on Chemical Intermediates - A magnetic graphitic carbon nitride (g-C3N4) nanocomposite was prepared and used as a novel magnetically retrievable nanocatalyst for efficient ring opening of... 相似文献
155.
Low capacity adsorbents, based on iminodiacetic acid and a crosslinked agarose, Novarosetrade mark, have been synthesised for the enrichment of metal ions. Test ions Cu(2+) with high, and Cd(2+) with a moderate affinity for the sorbent were selected. The study includes the effect of specific capacity and matrix composition on the rate of uptake and recovery of these ions. Using a column packed with 0.25 ml of a sorbent and a sample volume of 100 ml, Cu(2+) is quantitatively accumulated from all of the matrices studied even at a capacity of 6 mumol ml(-1) of adsorbent and a flow rate as high as 100 ml min(-1). The enrichment of Cd(2+) is affected by the matrix and for quantitative recovery the flow rate and capacity must be properly adjusted. In the presence of 0.01 M Ca(2+), a specific capacity of 45 mumol ml(-1) is needed for quantitative retainment and a flow rate of 100 ml min(-1), whereas a capacity of 10 mumol ml(-1) suffices at 10 ml min(-1). The advantage of low specific capacity on the removal of matrix elements has been demonstrated. A method based on the determination of conditional stability constants of the metal sorbent complex is suggested for predicting the sorbent capacity needed to acquire quantitative recovery and optimal matrix elimination. 相似文献
156.
Sajad Saberi Sarmoor S. Jafar Hoseini Roghayeh Hashemi Fath Mahmoud Roushani Mehrangiz Bahrami 《应用有机金属化学》2018,32(1)
PtSnZn nanosheet thin film with stable and high activity towards methanol electro‐oxidation was synthesized via a simple reduction of organometallic precursors including [PtCl2(cod)] (cod = cis,cis‐1,5‐cyclooctadiene) and [Sn(CH3)4] complexes, in the presence of [Zn(acac)2] (acac = acetylacetonate) complex at toluene–water interface. Catalytic activities of PtSnZn nanosheets were investigated in the p‐nitrophenol (p‐Nip) reduction and methanol oxidation reactions. The obtained results demonstrate that PtSnZn nanosheets exhibit a good electrocatalytic performance for methanol oxidation reaction, the catalytic activity of the PtSnZn nanosheets being at least 3.5 times higher than that of Pt nanoparticle thin film. Also, the apparent rate constant obtained for p‐Nip reduction with the PtSnZn nanosheets is at least 2.3 times higher than that for Pt nanoparticle thin film due to the appropriate interaction between platinum, tin and zinc metals and geometric properties of PtSnZn nanosheet thin film. Nanosheets are highly favourable for superior catalytic performances due to their geometric properties. A facile and efficient route was used to synthesize trimetallic alloy thin film at oil–water interface. 相似文献
157.
Heidari Behzad Shiroud Cheraghchi Vajiheh-Sadat Motahari Siamak Motlagh Ghodratollah Hashemi Davachi Seyed Mohammad 《Journal of Sol-Gel Science and Technology》2018,88(1):236-248
Journal of Sol-Gel Science and Technology - Resorcinol formaldehyde (RF) xerogel was modified by mercapto functional groups for removal of Pb(II) and Cu(II) ions from aqueous solutions. The... 相似文献
158.
159.
Mohammad Hossein Habibi Payman Bagheri 《Journal of the Iranian Chemical Society》2017,14(8):1643-1649
Spinel cobalt manganese oxide nano-composites were grown on nanosheets using acetate precursors in mono-ethylene glycol. Crystal structures and morphologies of nano-composites were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy and energy dispersive X-ray spectroscopy to characterize the element composition. Fourier transform infrared spectroscopy was used for structural characterization and UV–Vis diffuse reflectance spectra (UV–Vis DRS) for optical properties. XRD results showed tetragonal spinel cobalt manganese oxide (Co,Mn)(Co,Mn)2O4 and cubic spinel cobalt manganese oxide MnCo2O4.5 structural phases. The crystallite size calculated by the Scherrer’s equation was 17 nm. The morphological studies displayed the existence of 40–63 nm nano-powders grown on nanosheets with a good degree of crystallization. Optical properties of cobalt manganese oxide nano-composites exhibit absorbance edge, and the band gap calculated from UV–Vis DRS results was 1.78 eV. FTIR spectra indicated that hydroxyl and oxide groups were major active sites. The absorption bands observed at 656 and 568 cm?1 are related to stretching vibrations of Mn–O and Co–O, respectively. The photocatalytic activities of nano-composites for photocatalytic mineralization of Acid Black 1 textile dye showed an outstanding performance. Photocatalytic process yielded 91% total organic carbon removals within 2.5 h of irradiation. The enhanced photocatalytic activity was attributed to better charge separation of the photo-generated electron–hole pairs in nano-composite. 相似文献
160.
Using the most recent phase shift data for pp, nn,
and np elastic scattering for different states (l=0,1,…) in the energy range
of 1 MeV to 350 MeV, the charge dependency of the strong nuclear force
is investigated. Our results indicate that although the charge
independency holds in most of the energy range, such charge
independency is broken in the particular energy range of 120 MeV to
200 MeV for all partial wave states considered here. 相似文献