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71.
We describe a novel method for the synthesis a new magnetic bromochromate hybrid nanomaterial, Fe3O4@SiO2@TEA@[CrO3Br], as a catalyst. The physical properties, morphology and magnetic investigations of magnetic bromochromate hybrid nanomaterials are identified by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM) techniques. Fourier transform infrared (FT-IR), elemental analysis, X-ray fluorescence (XRF), X-ray diffraction (XRD) were also used for structural identification. The quantity of chromium is approximately 0.38%, which confirms to the immobilization amount of [CrO3Br]- and is equal to 0.007 mol/100 g. 相似文献
72.
The Raman linewidths of the carbon-halogen stretching mode in several halobenzenes were measured as a function of temperature and in dilute cyclohexane solution. It was found that, as in an earlier investigation on haloalkanes, the vibrational relaxation efficiencies, τ?1iso, vary in the order Cl > Br > I. The temperature dependence of τiso, together with the results in dilute solution, provide evidence that dipolar interactions play a significant role in vibrational relaxation in these systems. 相似文献
73.
Ghassempour A Najafi NM Mehdinia A Davarani SS Fallahi M Nakhshab M 《Journal of chromatography. A》2005,1078(1-2):120-127
A simple and sensitive method for determining anatoxin-a in aqueous samples was developed using solid-phase microextraction (SPME) and gas chromatography with mass spectrometry (GC-MS) detection. Three forms of polyaniline (PANI) films and a single form of polypyrrole (PPY) film were prepared and applied for SPME. The extraction properties of these films to anatoxin-a were examined and it was shown that leucoemeraldine form of PANI displayed a better selectivity to this compound. SPME conditions were optimized by selecting the appropriate extraction parameters, including type of coating (leucoemeraldine form of PANI at 32 microm thicknesses), salt concentration (10%, w/v), time of extraction (30 min) and stirring rate (1000 rpm). The calibration curve was linear in the range from 50 to 10,000 ng/ml, with the detection limit (S/N = 3) of 11.2 ng/ml. This method was successfully applied for the analysis of anatoxin-a in the cultured media of two species of cyanobacteria. 相似文献
74.
The Atomic Energy Commission of Syria (AECS), in cooperation with the Arabic Atomic Energy Agency (AAEA), has initiated the
first proficiency test exercise for the determination of naturally occurring radioactive materials (NORM) in contaminated
soil from the oil field. The soil sample was collected from one of the most highly radioactively contaminated lagoons with
production water in the Syrian oil fields, which was then prepared, characterised and certified according to a standard procedure.
Samples were dispatched to laboratories from eight Arab countries; Kuwait, Egypt, Yemen, Tunisia, Jordan, the Kingdom of Saudi
Arabia, Libya and Syria. The results were evaluated using three statistical criteria; z-score, the U
test score and the relative bias. These statistical methods were used to evaluate the performance of each laboratory, in addition
to the overall evaluation for each radionuclide. This evaluation has indicated that 57% and 86% of the results passed the
criteria set for precision and accuracy applied for this test in relation to 226Ra and 228Ra, respectively. These two radionuclides are considered to be the most important radionuclides in the oil industry. 相似文献
75.
Riahi S Ganjali MR Moghaddam AB Norouzi P Hosseiny Davarani SS 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2008,70(1):94-98
Computational studies have been carried out at the DFT-B3LYP/6-31G(d) level of theory on the structural and spectroscopic properties of 2-(1-oxo-1 H-inden-3-yl)-2H-indene-1,3-dione (OID). Experimental studies were conducted on these parameters, including X-ray, FT-IR and 13C NMR spectroscopy. The optimized geometries of OID and its bonding characteristics as well as IR and NMR spectra have been calculated and analyzed. It was observed that the bond lengths and angles in the molecule, obtained by X-ray, IR and NMR at the level of theory, were in a good agreement with those of the experiment. The correlation between the theoretical and the experimental vibrational frequencies and the chemical shifts of the OID molecule were 0.994 and 0.991, respectively. The agreement mutually verified the accuracy of the experimental method and the validity of the applied mathematical model. 相似文献
76.
The hitherto unknown 5‐(2‐aryl‐2‐oxoethyl)‐4‐oxo‐1,3‐thiazolidines 1a‐l have been synthesized viacycloaddition process between thiourea and/or its derivatives with 3‐aroylpropenoic acids. 1H NMR spectra revealed the presence of 1a‐c as a tautmeric mixture. The presence of the thiazoline tautmers (1a‐c) ′ was confirmed by methylating the tautmeric mixture, to the respective methylated derivatives 2‐N‐methylanilino‐5‐(2‐aryl‐2‐oxoethyl)‐4‐oxo‐1,3‐thiazolines 2a‐c and 1g‐i . Acidic treatment of 1 provided the respective 2‐oxo homologues 3a‐i . When 1a‐d , k were refluxed with DMF, molecular rearrangement was achieved, providing the 4‐oxo‐2‐thioxoimidazolidine isomers 4a‐d , k . Bromination of 4a and 4d in hot acetic acid afforded the respective (E,Z)‐5‐benzoylmethylene derivatives 5a,d which were prepared authentically. Thiation of 1a‐c and 4a‐c gave 5‐aryl‐2,3‐dihydro‐2‐phenyliminothieno[2,3‐d]thiazoles 6a‐c and 1‐phenyl‐5‐aryl‐2,3‐dihydro‐2‐thioxothieno[2,3‐d]imidazoles 7a‐c , respectively. The proposed structures have been confirmed by elemental analysis and spectroscopic data. The selected products showed different antimicrobial effect. 相似文献
77.
Anti‐neurotoxic evaluation of synthetic and characterized metal complexes of thiosemicarbazone derivatives 下载免费PDF全文
Quinoline‐2‐caboxyaldehyde thiosemicarbazone (HL1) and quinoline ‐2‐caboxyaldehyde N‐dimethyl thiosemicarbazone (HL2) metal complexes were prepared and characterized using analytical and spectroscopic techniques. The measurements showed that ligands behave as monovalent or neutral tridentate ligands bonding via azomethine, quinoline ring nitrogen atoms and sulfur atoms in thiol or thion forms. The anti‐neurotoxic effect of ligands and their complexes showed that, exposure to aluminum increase oxidative stress in the brain, an effect that could be offset by concomitant thiosemicarbazone complexes. Complexes could be having an effect on absorption or excretion of aluminum, due to their chelating activity. These findings may shed light on the potential clinical importance of thiosemicarbazone complexes in Alzheimer's disease. 相似文献
78.
S. M. Hadji Saied 《Journal of Radioanalytical and Nuclear Chemistry》2001,249(3):665-667
The Bio-Rex 5 resin was used for the recovery of 123I, producedin a cyclotron by irradiation of a 124 Xe target. Initially fouranion exchange resins AG1-X8, AG2-X8, Amberlite IRA-93 and Bio-Rex 5 wereused, but none of them gave good separations. Bio-Rex 5, consisting of a largeportion of tertiary and a smaller portion of quaternary amino groups, wasthen modified so that the resin contained only tertiary amine functional groupsand this modified resin was used for the separation. The concentrations ofiodide solutions were ca 5 ppb and the volumes about 120 ml. For measurementof iodide, 131I was added as tracer. In this study 6 columns ofvarious sizes were used and the best of them, in terms of maximum recoveryand minimum volume of NaOH for elution, was selected for routine production. 相似文献
79.
Abdollah Salimi Loghman Mohamadi Rahman Hallaj Saied Soltanian 《Electrochemistry communications》2009,11(6):1116-1119
For the first time silicon carbide nanoparticles (SiC) was used for electrode modification and electrocatalytic oxidation of insulin. In comparison to bare glassy carbon (GC) electrode, the oxidation of insulin at GC electrode modified with SiC nanoparticles occurred at reduced overpotentials. The modified electrode was applied for insulin detection using cyclic voltammetry, differential pulse voltammetry (DPV) and flow injection analysis (FIA). Flow injection amperometric determination of insulin at this modified electrode yielded a calibration curve with the following characteristics; linear dynamic range up to 600 pM, sensitivity of 710 pA pM?1 cm?2 and detection limit of 3.3 pM. In addition interference effect of the electroactive existing species (uric acid, glucose, lactic acid, l-cysteine and cholesterol) was diminished and for ascorbic acid eliminated by covering the surface of modified electrode with nafion film. This electrode shows many advantages as an insulin sensor such as simple preparation method without using any specific electron transfer mediator or specific reagent, high sensitivity, excellent catalytic activity, short response time, long term stability and remarkable antifouling property toward insulin and its oxidation product. Sensitivity, detection limit and antifouling properties of this insulin sensor are better than all of the reports in the literature for insulin detection at physiological pH solutions. 相似文献
80.
Simin D. Maleknia Kevin M. Downard 《Rapid communications in mass spectrometry : RCM》2012,26(19):2311-2318
The on‐plate deposition of oxidized proteins is described to advance footprinting applications by radical probe mass spectrometry (RP‐MS). An electrospray ionization (ESI) needle assembly mounted vertically over a 384‐target matrix‐assisted laser desorption/ionization (MALDI) plate enabled the limited oxidation of proteins as they were released in the charged droplets ahead of their deposition on the plate. This method combined with on‐plate proteolytic digestion protocols expedites the analysis of proteins oxidized by RP‐MS, and avoids the need to collect and reconstitute samples prior to analysis by MALDI mass spectrometry. Oxidation of peptides from solutions in water as well as an ammonium bicarbonate solution was investigated to test the optimal conditions required for on‐plate oxidation of proteins. These comprised of peptides with a wide range of reactive amino acids including Phe, Tyr, Pro, His, Leu, Met and Lys that were previously shown to oxidize in both electrospray discharge and synchrotron radiolysis based footprinting experiments. The on‐plate deposition of lysozyme oxidized at electrospray needle voltages of 6 and 9 kV were carried out to demonstrate conditions suitable for footprinting experiments as well as those that induce the onset of protein damage. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献