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501.
Polyfunctional 1,4-disubstituted piperazines were successfully synthesized stereoselectively via a one-pot, five-component Ugi/nucleophilic addition reaction sequence. Regio- and stereo-selective addition of piperazine to an activated alkyne under catalyst-free conditions and high yields of products are advantages of this method. 相似文献
502.
503.
The non-toxic and magnetically separable nano-CuFe_2O_4 catalyzed synthesis of symmetrical aryl sulfides by the reaction of thiourea with a wide variety of aryl halides,including aryl chlorides has been reported.Excellent yields of products have been obtained under ligand-free conditions and without the use of any expensive catalyst,such as palladium. 相似文献
504.
Mojtaba Shamsipur Ahmad Soleymanpour Morteza Akhond Hashem Sharghi Mohammad Ali Naseri 《Analytica chimica acta》2001,450(1-2):37-44
A new modified carbon paste electrode (CPE) based on a recently synthesized Schiff base complex of Fe(III) as a suitable carrier for I− ion is described. The electrode exhibits a super Nernstian slope of 71.0±0.3 mV per decade for I− ion over a wide concentration range from 1.0×10−6 to 5.0×10−1 M, with a low detection limit of 6.5×10−7 M. It has a relatively fast response time, a satisfactory reproducibility and relatively long life time. The proposed sensor shows a fairly good selectivity toward I− ion in comparison to other common anions. The potentiometric response is independent of the pH of the test solution in the pH range 3.5–10.0. Spectrophotometric studies confirmed the redox-type response mechanism of the electrode toward iodide ion. The proposed electrode was used as an indicator electrode in potentiometric titration of iodide ion. 相似文献
505.
Optical properties of TiO2 nanowires, synthesized by two-step thermal evaporation process, have been studied experimentally and theoretically. Based on the theoretical method optical constants of nanowires have been calculated with the use of the effective medium approximation (EMA). As evidenced by X-ray diffraction patterns our synthesized nanowires, whose diameters and lengths were within the ranges of 50-90 nm and 500-1500 nm, respectively, were found to be crystalline rutile TiO2 with the major refraction being along the (1 1 0) direction. The experimental data of the reflectance of TiO2 nanowires has been obtained using spectrometer in wavelength 250-800 nm, and then, compared with the spectrum of reflectance predicted by the EMA theoretical model. Our measured experimental optical data has been found to be in good accord with our predicted results spectrum with the use of the EMA modeling; this agreement indicates that our estimation of the volume fraction from atomic force microscopy (AFM) data was accurate. 相似文献
506.
Morteza Rasti Barzoki Morteza JahanbaziMehdi Bijari 《Applied mathematics and computation》2011,217(21):8328-8336
The economic production quantity (EPQ) is one of the most widely known inventory control models that can be regarded as the generalized form of the Economic Order Quantity. However, the model is built on an unrealistic assumption that all the produced items need to be of perfect quality. Also, the introduction of work in process, WIP, as part of the inventory has been of lesser concern in developing inventory models. This paper attempts to develop the economic production quantity considering work in process inventory and manufacturing imperfect products that may be either reworkable or non-reworkable. The non-reworkable imperfect products are sold at a reduced price. This paper introduces a new model for this problem. 相似文献
507.
Due to their unique magnetic properties, excellent biocompatibility as well as multi-purpose biomedical potential (e.g., applications in cancer therapy and general drug delivery), superparamagnetic iron oxide nanoparticles (SPIONs) are attracting increasing attention in both pharmaceutical and industrial communities. The precise control of the physiochemical properties of these magnetic systems is crucial for hyperthermia applications, as the induced heat is highly dependent on these properties. In this review, the limitations and recent advances in the development of superparamagnetic iron oxide nanoparticles for hyperthermia are presented. 相似文献
508.
Non-saturated lipids in the lung surfactant are prone to oxidation by oxidative species present in air. In this Letter, oxidized monolayers of dioleoylphosphatidylcholine (DOPC) were studied by means of both molecular dynamics and potential of mean force calculations. Structural changes of the monolayer following oxidation were revealed, including orientational reversal of oxidized chains. Accumulation of oxidized lipids in the monolayer is observed for moderate oxidation ratios, whereas removal of the short-chain oxidation product is predicted at long timescales. Massive oxidation leads to the loss of the well-ordered monolayer structure and partial solubilization of the oxidized lipids in the aqueous subphase. 相似文献
509.
Ahmad Hasanpour Morteza Mozafari Mohammad-Reza Azani Azin Hassanpour 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2012,86(2):264-267
In this work Bi-Fe3O4 nanocomposite was synthesized by room temperature milling of Bi2O3 and Fe powders using a planetary ball mill in air. The synthesis reaction proceeds with increase in milling time and is finished
by about 4 h. The XRD pattern of the as-milled powder shows that the main phases are Bi and Fe3O4 without any extra phases. The average crystallite sizes of the constituents have been determined by Scherrer’s formula and
they were 22 and 18 nm for Bi and Fe3O4 respectively. This was also confirmed by Transmission Electron Microscopy (TEM). Magnetic hysteresis loops at room temperature
were recorded using a vibrating sample magnetometer (VSM). A tow-probe method was used to measure resistivity variation of
the nanocomposite as a function of magnetic filed and temperature. We have observed a room temperature magnetoresistance (ρ0 — ρ
H
)/ρ0 as large as 17% in a magnetic field of 1 T. 相似文献
510.
Bita SoleymanifardMajid M. Heravi Morteza Shiri Mohammad Ali ZolfigolMohammad Rafiee Hendrik G. KrugerTricia Naicker Farzaneh Rasekhmanesh 《Tetrahedron letters》2012,53(28):3546-3549
Arylidenepyruvic acids (APAs) have been successfully employed in an Ugi-four component condensation reaction which yielded polyfunctional amides. Condensation of various APAs, aldehydes, amines, and isocyanides at room temperature in 96% ethanol as a green solvent proceeded in good yields. The extension of the reaction to diamines, formaldehyde, and isocyanides to form more complex molecules is also reported. These novel products may have potential in various pharmaceutical applications. 相似文献