排序方式: 共有49条查询结果,搜索用时 31 毫秒
41.
Florica Manea Ciprian Radovan Ioana Corb Aniela Pop Georgeta Burtica Plamen Malchev Stephen Picken Joop Schoonman 《Electroanalysis》2008,20(15):1719-1722
An expanded graphite‐epoxy composite electrode (EG‐Epoxy) was employed for the simultaneous determination of 4‐chlorophenol (4‐CP) and oxalic acid (OA) by using cyclic voltammetry (CV), chronoamperometry (CA), and differential pulse voltammetry (DPV). The results indicated that OA could be determined in the presence of the same concentrations of 4‐CP within the concentration range of 0.1 mM to 0.5 mM with a relative standard deviation (RSD) smaller than 5%. Electrode fouling occurred during CA for 4‐CP concentrations larger than 0.5 mM. The DPV method was used for the simultaneous determination of 4‐CP and OA before and after electrochemical oxidation by chronopotentiometry under galvanostatic conditions (j=0.04 mA cm?2, t=2 h) of a tap water sample spiked with 0.19 mM 4‐CP and 0.1 M Na2SO4. 相似文献
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Vlad Cozma Irina Rosca Luminita Radulescu Cristian Martu Valentin Nastasa Cristian-Dragos Varganici Elena-Laura Ursu Florica Doroftei Mariana Pinteala Carmen Racles 《Molecules (Basel, Switzerland)》2021,26(16)
Within this study, new materials were synthesized and characterized based on polysiloxane modified with different ratios of N-acetyl-l-cysteine (NAC) and crosslinked via UV-assisted thiol-ene addition, in order to obtain efficient membranes able to resist bacterial adherence and biofilm formation. These membranes were subjected to in vitro testing for microbial adherence against S. pneumoniae using standardized tests. WISTAR rats were implanted for 4 weeks with crosslinked siloxane samples without and with NAC. A set of physical characterization methods was employed to assess the chemical structure and morphological aspects of the new synthetized materials before and after contact with the microbiological medium. 相似文献
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Cornelia Vasile Elena Maria Clugru Silvia Florica Bodonea 《Journal of polymer science. Part A, Polymer chemistry》1981,19(4):897-905
The influence of the degree of hydrolysis on thermoxidative degradation of the poly(vinyl alcohol) was studied. The thermoxidative degradation was carried out under dynamic thermal conditions. Taking into account the dependence of the activation energy values on the heating rate, molecular weight, degree of conversion, and degree of hydrolysis, some conclusions were drawn about the decomposition mechanism and the variation of the thermal stability. 相似文献
44.
General Uniqueness Results and Variation Speed for Blow-Up Solutions of Elliptic Equations 总被引:7,自引:0,他引:7
Let be a smooth bounded domain in RN. We prove general uniquenessresults for equations of the form u = au b(x)f(u) in , subject to u = on . Our uniqueness theorem is establishedin a setting involving Karamata's theory on regularly varyingfunctions, which is used to relate the blow-up behavior of u(x)with f(u) and b(x), where b 0 on and a certain ratio involvingb is bounded near . A key step in our proof of uniqueness usesa modification of an iteration technique due to Safonov. 2000Mathematics Subject Classification 35J25 (primary), 35B40, 35J60(secondary). 相似文献
45.
Petrú Spacu und Florica Popea 《Fresenius' Journal of Analytical Chemistry》1963,195(4):251-254
Zusammenfassung Uran wird durch Essigsäureäthylester aus einer Salpetersäure und NH4NO3 enthaltenden Lösung ausgeschüttelt, und das in der wäßrigen Lösung verbliebene Thorium in der essigsauer gepufferten Lösung mit Na-m-Nitrobenzolazosalicylat gefällt. ThO2 wird zur Gewichtskonstanz geglüht. 相似文献
46.
Barzic Andreea Irina Soroceanu Marius Rotaru Razvan Doroftei Florica Asandulesa Mihai Tugui Codrin Dascalu Ioan Andrei Harabagiu Valeria 《Cellulose (London, England)》2022,29(2):863-878
Cellulose - This work deals with hydroxypropyl cellulose (HPC)/barium titanate (BT) composites, having small levels of perovskite-like BT loading, i.e. 0.5–2% and being designed for electric... 相似文献
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A non-enzymatic direct electrochemical glycerol detection method at a commercial boron-doped diamond (BDD) electrode in 0.1 M NaOH supporting electrolyte was developed. All the used electrochemical techniques proved useful features for the oxidation and direct amperometric determination of glycerol at a BDD electrode in 0.1 M NaOH aqueous solution. It was found that the direct electrooxidation of glycerol on the BDD electrode requires both adsorbed glycerol and hydroxyls at the electrode surface. Also, the sp(2) carbon did not allow enhancement of the glycerol oxidation process. The electronalytical sensitivity for the determination of glycerol at the BDD electrode ranged from 0.040 to 0.226 μA mM(-1) as a function of the technique used. The highest electroanalytical sensitivity for the determination of glycerol at the BDD electrode was reached in batch system amperometric quantification under stirring conditions. Performed recovery studies indicated that it is possible to determine glycerol in real samples, and the proposed batch system analysis-based methodology can be a valuable tool for practical glycerol analysis. 相似文献
49.
Dr. Ion Bunia Dr. Vlad Socoliuc Dr. Ladislau Vekas Dr. Florica Doroftei Dr. Cristian Varganici Dr. Adina Coroaba Prof. Bogdan C. Simionescu Dr. Marcela Mihai 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(50):18036-18044
The preparation of superparamagnetic composites obtained by CaCO3 mineralization from supersaturate aqueous solutions is presented. The preparation was conducted in the presence of oleic acid stabilized magnetite nanoparticles as a water‐based magnetic fluid and insoluble templates as gel‐like cross‐linked polymeric beads. The presence of the magnetic particles in the composites provides a facile way for external manipulation using a permanent magnet, thus allowing the separation and extraction of magnetically modified materials. Two ion exchangers based on divinylbenzene/ethyl acrylate/acrylonitrile cross‐linked copolymer—a cation ion exchanger (CIE) and an amphoteric ion exchanger (AIE)—were used, as well as different addition orders of magnetite and CaCO3 crystals growth precursors. The morphology of the composites was investigated by SEM, the polymorphs content by X‐ray diffraction, and the thermal stability by thermogravimetric analysis. Polymer, CaCO3, and magnetite in the composite particles were shown to be present by energy dispersive X‐ray (EDX), XPS, and TEM. The sorption capacity for CuII ions was tested, as compared to samples prepared without magnetite. 相似文献