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1.
Highly Efficient Copper(II) Ion Sorbents Obtained by Calcium Carbonate Mineralization on Functionalized Cross‐Linked Copolymers
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Dr. Marcela Mihai Dr. Ion Bunia Florica Doroftei Dr. Cristian‐Dragos Varganici Prof. Bogdan C. Simionescu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(13):5220-5230
A new type of CuII ion sorbents is presented. These are obtained by CaCO3 mineralization from supersaturated solutions on gel‐like cross‐linked polymeric beads as insoluble templates. A divinylbenzene–ethylacrylate–acrylonitrile cross‐linked copolymer functionalized with weakly acidic, basic, or amphoteric functional groups has been used, as well as different initial inorganic concentrations and addition procedures for CaCO3 crystal growth. The morphology of the new composites was investigated by SEM and compared to that of the unmodified beads, and the polymorph content was established by X‐ray diffraction. The beads, before and after CaCO3 mineralization, were tested as sorbents for CuII ions. The newly formed patterns on the bead surface after CuII sorption were observed by SEM, and the elemental distribution on the composites and the chemical structure of crystals after interaction with CuII were investigated by EDAX elemental mapping and by FTIR‐ATR spectroscopy, respectively. The sorption capacity increased significantly after CaCO3 crystals growth on the weak anionic bead surface (up to 1041.5 mg CuII/g sample) compared to that of unmodified beads (491.5 mg CuII/g sample). 相似文献
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Manea S. AlKhalifah Chunhong Lei Steven A. Myers Stuart P. Kitney 《Liquid crystals》2013,40(3):402-417
The cross-linking of polymerisable liquid crystalline semiconductors is a promising approach to solution-processable, multilayer, organic photovoltaics. Here we demonstrate an organic bilayer photovoltaic with an insoluble electron-donating layer formed by cross-linking a nematic reactive mesogen. We investigate a range of perylene diimide (PDI) materials, some of which are liquid crystalline, as the overlying electron acceptor layer. We find that carrier mobility of the acceptor materials is enhanced by liquid crystallinity and that mobility limits the performance of photovoltaic devices. 相似文献
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Marian Vîrgolici Corneliu Ponta Mihaela Manea Daniel Neguţ Mihalis Cutrubinis Ioan Moise Rareş Şuvăilă Eugen Teodor Costel Sârbu Andrei Medvedovici 《Journal of chromatography. A》2010,1217(12):1977-1987
Research on the chemical composition of fossil resins has evolved during the last decades as a multidisciplinary field and is strongly oriented toward the correlation with their geological and botanical origin. Various extraction procedures and chromatographic techniques have been used together for identifying the volatile compounds contained in the fossil resin matrix. Hyphenation between thermal desorption (TD), gas chromatography (GC) and mass spectrometry detection (MS) has been chosen to investigate the volatile compounds fraction from ambers with a focus on Romanite (Romanian amber) and Baltic amber species. A data analysis procedure was developed for the main purpose of fingerprinting ambers based on the MS identity of the peaks generated by the volatile fraction, together with their relative percentual area within the chromatogram. Chromatographic data analysis was based entirely on Automated Mass Spectral Deconvolution & Identification System (AMDIS) software to produce deconvoluted mass spectra which were used to build-up a mixed mass spectra and relative retention scale library. Multivariate data analysis was further applied on AMDIS results with successful discrimination between Romanite and Baltic ambers. A special trial was conducted to generate pyrolysis “like” macromolecular structure breakdown to volatile compounds by gamma irradiation with a high absorbed dose of 500 kGy. Contrary to our expectations the volatile fraction fingerprints were not modified after irradiation experiments. A complementary non-destructive new approach by ESR spectroscopy was also proposed for discriminating between Romanite and Baltic ambers. 相似文献
6.
Carmen Racles Iuliana Stoica Florica Doroftei Vasile Cozan 《Journal of nanoparticle research》2011,13(12):6971-6980
Polysulfone?silver composite nanoparticles have been prepared by combining polymer nanoprecipitation and redox synthesis of silver, in the presence of a glucose-modified cyclosiloxane as stabilizing agent. Based on previous kinetic investigations and on model reactions, we concluded that the reducing agent in this case is the tetrahydrofuran (THF) used as solvent for polysulfone. Dynamic light scattering measurements on the obtained polymer-silver composite particles indicated particle average diameter of 176 nm with a polydispersity index of 0.25. The UV–vis spectrum exhibited the silver plasmon resonance. By different microscopic methods (atomic force microscopy—AFM, high resolution transmission electron microscopy—HRTEM, and scanning electron microscopy—SEM), larger polymer particles coated with silver nanoprticles were observed. The Energy Dispersive X-Ray analysis—EDX; confirmed the presence of Ag on the surface of the particles, while the selected area electron diffraction showed single crystalline silver nanospheres with face-centered cubic structure. 相似文献
7.
Dr.-Ing. H. Försching Dr.-Ing. V. Manea 《Archive of Applied Mechanics (Ingenieur Archiv)》1973,42(3):178-193
Übersicht Es wird ein graphisch-numerisches Verfahren zur Lösung der nichtlinearen Galloping-Differential- gleichung dargelegt. Die Einzelheiten des Lösungsverfahrens werden beschrieben und an Hand eines typischen Beispiels näher erläutert.
Diese Arbeit entstand im Rahmen eines einjährigen Stipendiums der Alexander von Humboldt-Stiftung. Der Stipendiat Dr.-Ing. V. Manea ist Mitarbeiter im Institut de Mecanica Fluidelor si Constructii Aerospatiale, Bukarest. 相似文献
Summary A graphical-numerical method for the solution of the non-linear Galloping differential equation is presented. The details of the analytical procedure are discussed and explained by means of a typical example.
Diese Arbeit entstand im Rahmen eines einjährigen Stipendiums der Alexander von Humboldt-Stiftung. Der Stipendiat Dr.-Ing. V. Manea ist Mitarbeiter im Institut de Mecanica Fluidelor si Constructii Aerospatiale, Bukarest. 相似文献
8.
New PP/PLA/cellulose composites: effect of cellulose functionalization on accelerated weathering behavior (accelerated weathering behavior of new PP/PLA/cellulose composites)
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Raluca Nicoleta Darie Stelian Vlad Narcis Anghel Florica Doroftei Tarja Tamminen Iuliana Spiridon 《先进技术聚合物》2015,26(8):941-952
Polylactic acid (PLA) was used as partial replacement for conventional thermoplastic matrix, new composites comprising cellulose, polypropylene (PP), and PLA being realized. In order to obtain a compatible interface between cellulosic pulp and polymeric matrix, two chemical modifications of cellulose with stearoyl chloride and toluene di‐isocyanate (TDI) were performed, structural changes being evidenced by X‐ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The composite materials were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, dynamic scanning calorimetry, impact, tensile and melt rheological tests, surface tension, and dynamic vapor sorption. Because promising results for impact strength and Young modulus were recorded when replacing 15% of PP with PLA in blends of PP with the same cellulosic pulp load, the aim of our study was to assess the behavior to accelerate weathering of composites comprising PP, cellulosic pulp, and PLA. Although the slight decrease in the mechanical properties was recorded after accelerated weathering, the use of functionalized cellulose successfully prevented the deterioration of surface materials, especially for composite comprising stearoyl chloride treated cellulose pulp. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
9.
Raluca Dumitru Florica Manea Lavinia Lupa Cornelia Păcurariu Adelina Ianculescu Anamaria Baciu Sorina Negrea 《Journal of Thermal Analysis and Calorimetry》2017,128(3):1305-1312
Nanosized cobalt aluminate (CoAl2O4) was prepared by thermolysis of heteronuclear coordination compound, namely [Al2Co(C2O4)4(OH2)6]. The synthesized precursor was characterized by chemical analysis, vibrational spectra and thermal analysis. The cobalt aluminate obtained after a heating treatment of the precursor at 700 °C was characterized by IR, XRD, TEM coupled with SAED measurements. Two types of carbon-based electrodes, glassy carbon and boron-doped diamond electrodes were decorated with the obtained cobalt aluminate in order to enhance the electroanalytical performance for the tetracycline (TC) detection in the aqueous solutions. Cyclic voltammetry technique was used to determine the effect of the nanosized CoAl2O4 on the electrochemical oxidation of TC and as consequence, for TC detection at both carbon-based electrodes. The obtained cobalt aluminate exhibited the electrocatalytic activity toward TC detection in direct relation with the type of the carbon substrate, which allowed enhancing the electroanalytical parameters of TC detection in the aqueous solution. 相似文献
10.
Cornelia Ratiu Florica Manea Carmen Lazau Corina Orha Georgeta Burtica Ioan Grozescu Joop Schoonman 《Chemical Papers》2011,65(3):289-298
This paper reports the results of an investigation into enhancement of the electrochemical oxidation of p-aminophenol (4-AP) in an aqueous solution with a boron-doped diamond (BDD) electrode, assisted by photocatalysis using a
zeolite-supported TiO2 (Z-TiO2) catalyst. The BDD electrode was characterised in 0.1 M Na2SO4-supporting electrolyte and the presence of 4-AP by open-circuit potential behaviour (OCP) and cyclic voltammetry (CV). The
electrode behaviour was investigated in the dark and following UV irradiation and in the absence/presence of the Z-TiO2 catalyst. The electro-oxidation process was carried out using chronoamperometry (CA) and multiple-pulsed amperometry (MPA)
at the selected potential under potentiostatic conditions. The electrochemical degradation process of 4-AP on the BDD electrode
was improved by the application of a pulsed potential, which allowed both in-situ electrochemical cleaning of the electrode
and indirect oxidation of 4-AP by oxygen evolution. The application of photocatalysis using Z-TiO2 in the 4-AP electrochemical degradation exhibited an enhanced effect when the anodic potential was set at +1.25 V vs. Ag/AgCl
in the water stability region, close to the oxygen evolution potential. 相似文献