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81.
Queueing Systems - We consider a matching system with random arrivals of items of different types. The items wait in queues—one per item type—until they are “matched.” Each... 相似文献
82.
Mir Fazlollah Mousavi Mojtaba Shamsipur Siavash Riahi Mohammad Safy Rahmanifar 《Analytical sciences》2002,18(2):137-140
A new, simple, sensitive, low cost and rapid potentiometric method for direct determination of ultra trace amounts of sodium dodecyl sulfate (SDS) with a new DS(-)-selective electrode is reported. The electrode was prepared by electropolymerization of aniline in acidified DS- ion on the surface of a Pt electrode. The cyclic voltammetry (CV) was used for electropolymerization of polyaniline (PA) in the potential range of -200 to +1000 mV vs. Ag/AgCl. This sensor showed a Nernstian behavior (59.0 +/- 2.3 mV/decade) over a very wide linear range (1.0 x 10(-9)-3.0 x 10(-6) M) with a detection limit of 1.0 x 10(-9) M. The response time of the electrode was 15 s for 1.0 x 10(-7) M of analyte; the electrode can be used for 4 weeks without any major deviation. This electrode can be used in the pH range of 3.5-9.8. The selectivity of electrode to DS- over some organic, inorganic and anionic surfactants was investigated with the fixed primary ion method. The results show that the electrode is highly selective to DS- ion over other ions. The proposed electrode was applied to the determination of DS- in real samples. 相似文献
83.
Mohammadreza Khalesi Kurt Gebruers David Riveros-Galan Sylvie Deckers Ali Akbar Moosavi-Movahedi Hubert Verachtert 《液相色谱法及相关技术杂志》2016,39(3):111-118
Purification is a critical step to obtain hydrophobin HFBII for use in positive applications. In this study, hydrophobin HFBII was produced by Trichoderma reesei via submerged fermentation. Using the CO2-foam fractionation method yielded a fourfold increase in protein concentration. The foamate (αL-HFBII) was dried using a nano spray-dryer under optimal temperature. The gushing activity of the dried foamate (αS-HFBII) decreased. Addition of Tween 80 to the foamate before the drying process partially prevented the deactivation of hydrophobin HFBII. The purity of the powder was enhanced based on the theory of CO2-nanobubbles in a CO2-rich environment. The collected CO2-nanobubbles were added to an apolar–polar system and the interface of these two phases was collected. After evaporation of the apolar phase, the purity of the hydrophobins assembled on the surface of the liquid was significantly improved. 相似文献
84.
85.
Mohammadreza Riahi 《Optical Review》2016,23(3):442-447
In this article, the fabrication of a corner cube array retro-reflective structure is presented by using DLP-based 3D printing technology. In this additive manufacturing technology a pattern of a cube corner array is designed in a computer and sliced with specific software. The image of each slice is then projected from the bottom side of a reservoir, containing UV cure resin, utilizing a DLP video projector. The projected area is cured and attached to a base plate. This process is repeated until the entire part is made. The best orientation of the printing process and the effect of layer thicknesses on the surface finish of the cube has been investigated. The thermal reflow surface finishing and replication with soft molding has also been presented in this article. 相似文献
86.
Ali Kazemi Babahydari Reza Fareghi-Alamdari Shahrbanou Moradpour Hafshejani Hadi Amiri Rudbari Mostafa Riahi Farsani 《Journal of the Iranian Chemical Society》2016,13(8):1463-1470
HSiW-MOF, PMo-MOF, HPMo-MOF and PW-MOF were synthesized and characterized by elemental analysis, UV–Vis, FT-IR, cyclic voltammetry and XRD. These compounds were used as catalyst for the selective oxidation of alcohols by hydrogen peroxide. Within them, PW-MOF showed a higher catalytic activity compared to other catalysts in a similar reaction condition. Therefore, PW-MOF catalyst system was successfully used for the selective oxidation of the benzylic, linear and secondary alcohols to the corresponding aldehydes and ketones. Also, allylic alcohols were converted to the corresponding aldehydes with high conversion and significant selectivity. Moreover, PW-MOF was stable to leaching, behaved as true heterogeneous catalysts, easily recovered by filtration, and reused four times with the preserve of the catalytic performance. 相似文献
87.
Farshad?Karami Mohammadreza?KhanmohammadiEmail author Amir?Bagheri?Garmarudi 《Journal of the Iranian Chemical Society》2016,13(12):2283-2289
Desulfurization of petroleum derivatives has been one of the main concerns of producers. Application of adsorption in desulfurization is one of the reliable strategies. Thus, development of new and better adsorbents is main goal of researchers. In this work, carbon nanofibers were coated with nickel by electroless plating method to be used in adsorption of 1-butanethiol (1-butyl mercaptan) for the first time. Nickel amount in these structures was varied and adsorption behavior studied. To characterize the prepared adsorbent, concentration variation of mercaptan was determined by attenuated total reflectance Fourier transform infrared spectroscopy with multivariate curve resolution–alternating least squares chemometrics method as a new way. Also, potentiometry method was used to determine the mercaptan concentration during the adsorption process as a standard method. The data which were achieved by the two mentioned methods are processed by sum of ranking differences chemometrics method separately to compare the adsorption behavior of adsorbents. By using sum of ranking differences, it was concluded that with increment in amount of coated nickel, adsorption capacity would increase and random behavior in adsorption process would decrease. Also, this study showed that attenuated total reflectance Fourier transform infrared spectroscopy with multivariate curve resolution–alternating least squares can be applied to study the concentration variations of mercaptan as a reliable method. 相似文献
88.
Gholamhassan Imanzadeh Aazam Aliabadi Mohammadreza Zamanloo 《Green Chemistry Letters and Reviews》2016,9(2):106-113
A regioselective N3-alkylation of 5,5-diphenyl-2-thiohydantoin (2-thiophenytoin) using a very efficient mild base K2CO3 and α,β-unsaturated esters in the presence of organic salt TBAB (tetrabutylammonium bromide) at room temperature has been reported (3b–3h). The selectivity of this reaction is excellent and products have been produced in good yields under solvent-free conditions. The increase of the reaction temperature to 70°C mostly disappeared this selectivity and afforded only the N1,N3-dialkylated derivatives of 2-thiophenytoin in good yields (4b–4g). We were unable to selectively N3-alkylate 2-thiophenytoin with ethyl acrylate at both room temperature and 70°C under the same conditions (4a). Dimethyl and diethyl fumarates cannot work as Michael acceptors and were hydrolyzed to fumaric acid under reaction conditions. 相似文献
89.
Rostampour Malihe Aboudzadeh Mohammadreza Sadeghi Mahdi Hamidi Saeid Alirezapour Behroz Soltani Naser Aslani Gholamreza 《Journal of Radioanalytical and Nuclear Chemistry》2017,314(3):1759-1766
Excitation functions and theoretical yields via charge particle induced reactions were evaluated using EMPIRE-3.2.2 and ALICE/ASH codes and the obtained results have been discussed and compared with the available reported experimental data. It has been verified that natCu(p,n)65Zn reaction is the optimum 65Zn production route. The 65Zn was produced using natCu(p,xn) 65Zn reaction in the energy range of 16.8 → 12.2 MeV with the thick target yield of 0.15 ± 0.005 MBq/μA h. The 65Zn radionuclide was purified by anion exchange chromatography.
相似文献90.
Hassan Ghavidel Behrooz Mirza Somayeh Soleimani-Amiri Mohammadreza Manafi 《中国化学会会志》2020,67(10):1856-1876
A green synthesis of functionalized 4H-chromenes using one-pot, three-component reaction of salicylaldehyde ( 1 ), active methylene ( 2 ), and carbon-based nucleophile ( 3 ) using Fe3O4@CONa nanoparticles in water has been performed at 60°C. The Fe3O4@CONa nanoparticle as an efficient, green, and magnetically reusable heterogeneous catalyst was applied in these reactions up to the nine runs. Green catalyst and solvent, short reaction time, high product yields, as well as simple work-up procedure were found as some advantages of this methodology. The density functional theory calculations were applied to all-inclusive perception of the one-pot, three-component reaction mechanism. The most reactions progressed through the following route: (a) nucleophilic addition of 2 to 1 ; (b) ring closing, dehydration; (c) nucleophilic substitution of 3 (2-naphtol, 4-hydroxycumarin) to intermediate. Sometimes mechanism mutated to: (a) nucleophilic addition of 3 (indole, 2-methylindole) to 1 , and dehydration; (b) nucleophilic addition of 2 to intermediate; and (c) ring closing, and dehydration. The frontier molecular orbitals, NBO analyses, molecular electrostatic potential of reactants, and intermediates confirmed the proposal mechanisms. Theoretical study could be so helpful to pick out suitable reactants of the reaction. 相似文献