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201.
The convective heat transfer coefficients resulting from a slot jet on a plane surface have been estimated by using the real measured temperatures in the plate and inverse method. In this study, the inverse method used the conjugate gradient method with an adjoint equation. Distributions of the local heat transfer coefficient on the impingement surface were determined for various Re and H/Dh. It was found the heat transfer coefficients generally tended to decrease with increasing separation distance and to increase with an increase in Reynolds number. This presented method is able to estimate the variation of the local Nusselt number with time. 相似文献
202.
The growth of sphere-like trimanganese tetraoxide (Mn3O4) nanoparticles on silk fiber was achieved by sequential dipping in an alternating bath of potassium hydroxide and manganese(II) nitrate under ultrasound irradiation. Some parameters such as the effect of pH, numerous sequential dipping and ultrasonic irradiation on growth of the nanoparticles have been studied. The samples were characterized with powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and wavelength dispersive X-ray (WDX). 相似文献
203.
Ali Rahmatpour Babak Kaffashi Somayeh Maghami 《Journal of Macromolecular Science: Physics》2013,52(9):1834-1846
Waterborne polyurethane (WBPU) was synthesized by a polyaddition reaction with toluene diisocyanate (TDI), polytetramethylene ether glycol (PTMEG), dimethylol propionic acid (DMPA), and triethylamine (TEA). Aqueous polyurethane dispersions with three different weight fractions, 30, 40, and 50 wt%, were prepared. All the dispersions made with these concentrations showed Newtonian viscosity behavior. Multiwalled carbon nanotubes (CNTs) were functionalized using a mixture of sulfuric and nitric acid at a ratio of 3:1 and added to these dispersions in two different loads of 0.1 and 0.5 wt%. Ultraviolet visible spectrometry (UV/Vis) spectroscopy proved the formation of stable suspensions following ultrasonic agitation. The rheology of these suspensions was characterized using dynamic and steady-state measurements. The higher amount of CNT in the suspension imparted non-Newtonian and complex viscoelastic behavior. This was attributed to a physical network formed due to the presence of the functionalized CNTs. The Cox-Merz rule was not observed for these suspensions. 相似文献
204.
Farshad Sohbatzadeh Abasalt Hosseinzadeh Colagar Saeed Mirzanejhad Somayeh Mahmodi 《Applied biochemistry and biotechnology》2010,160(7):1978-1984
We developed and employed a new geometrical structure of dielectric barrier discharge in atmospheric pressure for bacterial
broad spectrum sterilization. We utilized a plasma source having an AC power supply at 50 HZ and 5,400 V (rms value). We prepared
suspensions of the Gram-negative bacteria species (Escherichia coli, Pseudomonas aeruginosa) and a Gram-positive of Bacillus cereus with Luria–Bertani broth media up to OD600 nm = 0.25 of McFarland standard. Afterglow of non-thermal atmospheric pressure plasma treated these suspensions. The influence
of the atmospheric plasma afterglow on the species was assayed in different time durations 5, 10, and 15 min. The spectroscopic
results of this investigation indicated that the survival reduction of the species can reach to 100% for P. aeruginosa in an exposure time of 10 min, E. coli and B. cereus in an exposure time of 15 min. 相似文献
205.
Safar Irandoust-pakchin Hossein Kheiri Somayeh Abdi-mazraeh 《Computational Mathematics and Mathematical Physics》2013,53(7):920-932
In this paper, we introduce a modification of He’s variational iteration, homotopy analysis and optimal homotopy analysis methods for solving fractional boundary value problems. It is illustrated that the proposed methods are powerful fast numerical tools to find accurate solutions. It is illustrated that efficiency of these methods is based on proper choosing of initial guess. 相似文献
206.
Fazlollah Soleymani Mahdi Sharifi Bibi Somayeh Mousavi 《Journal of Optimization Theory and Applications》2012,153(1):225-236
In this paper, we first establish a new class of three-point methods based on the two-point optimal method of Ostrowski. Analysis
of convergence shows that any method of our class arrives at eighth order of convergence by using three evaluations of the
function and one evaluation of the first derivative per iteration. Thus, this order agrees with the conjecture of Kung and
Traub (J. ACM 643–651, 1974) for constructing multipoint optimal iterations without memory. We second present another optimal eighth-order class based
on the King’s fourth-order family and the first attained class. To support the underlying theory developed in this work, we
examine some methods of the proposed classes by comparison with some of the existing optimal eighth-order methods in literature.
Numerical experience suggests that the new classes would be valuable alternatives for solving nonlinear equations. 相似文献
207.
208.
Design of a novel optical sensor for determination of trace amounts of copper by UV–visible spectrophotometry in real samples
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Eslam Pourbasheer Somayeh Morsali Zhila Azari Mohammad Ali Karimi Mohammad Reza Ganjali 《应用有机金属化学》2018,32(3)
A new optical chemical sensor is established for sensitive and selective spectrophotometric detection of copper based on the immobilization of 3‐(2‐methyl‐2,3‐dihydro‐1,3‐benzothiezol‐2‐yl)‐2H‐chromen‐2‐one on a triacetylcellulose membrane. Copper ions react with the immobilized ligand and cause an increase in the absorption of the membrane at 550 nm in universal buffer solution at pH = 6. The effects of pH, indicator concentration and reaction time on the immobilization of the ligand were studied. This optode exhibits a linear range of 7.0 × 10?7 to 1 × 10?4 mol l?1 of copper ion concentration with a limit of detection of 3.0 × 10?7 mol l?1. The response time of the newly designed optode is within 3 min. The effect of different possible interfering species was investigated and it was found that the sensor has very good selectivity. The proposed sensor benefits from advantages such as low cost, high stability, low detection limit, fast response time, reproducibility, relatively long lifetime, and good selectivity for Cu2+ ion determination among a large number of alkali, alkaline earth, transition and heavy metal ions. The sensor can readily be regenerated with thiourea solution and its response is reversible and reproducible (relative standard deviation < 1.4%). The proposed optode was applied successfully for the determination of Cu(II) in various samples. 相似文献
209.
Reza Ranjbar-Karimi Somayeh Hashemi-Uderji Roghayeh Danesteh 《Journal of the Iranian Chemical Society》2012,9(5):747-755
Novel [6,6,6] ring fused tricyclic systems can be readily synthesized in one-pot annulation reaction of pentafluoropyridine or 4-phenylsulfonyl tetrafluoropyridine with appropriate difunctional nitrogen and oxygen nucleophiles attached to aromatic rings. Reaction of 4-phenylsulfonyl tetrafluoropyridine with 2,6-diaminopyridine gave [6,5,6] ring fused systems arising from a tandem SNAr and cyclisation process. From this investigation, di- and trifluorinated quinoxaline and dioxine scaffolds were synthesized. 相似文献
210.
A novel carbon paste electrode modified with graphene nanosheets and an ionic liquid (n-hexyl-3-methylimidazolium hexafluoro phosphate) was fabricated and used for the electrochemical study of mangiferin for the first time. This modified electrode offers a considerable improvement in voltammetric sensitivity toward mangiferin, compared to the bare electrode. Square wave voltammetry (SWV) exhibits a linear dynamic range from 5.0?×?10?8 to 2.0?×?10?4 M and a detection limit of 20.0 nM for mangiferin. Finally, the proposed method was successfully applied to the determination of mangiferin in real samples such as serum and urine. 相似文献