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11.
Nanocomposites from polyamide 11 and dried cellulose nanofibers (CNs), 16–30 nm in thickness and 50–400 nm in length, were prepared via direct melt mixing and their micro- and nano-mechanical properties were studied. (PF) QNM (Quantitative Nanomechanical Mapping) method was used to map nanomechanical properties at the surface of polyamide 11 and nanocomposites. This new AFM method emphasized both the increased modulus in nanocomposites as compared to the matrix and the microstructure on different levels in polyamide 11 and its nanocomposites. PF QNM showed that their crystalline structure consists of bundles of lamellar stacks, 200–350 nm in width and 20–40 nm wide lamellar stacks. Moreover, PF QNM study emphasized higher structural order in nanocomposites with 3 and 5 wt.% CNs and lower in the nanocomposite with 8 wt.% CNs as compared to the reference. These observations were verified and are consistent with both crystallinity values determined by DSC and micro-mechanical test results. The oriented bundles of lamellar stacks, observed by PF QNM, could be considered as the main blocks determining high mechanical properties for the studied nanomaterials. 相似文献
12.
I. Caplanus M. Marcu M. Cazacu Mihaela Vasiloschi G. I. Rusu 《Journal of Macromolecular Science: Physics》2013,52(5):727-737
The temperature dependence of the electrical conductivity and the Seebeck coefficient of some new complex polymeric structures containing metal chelate sequences alternating with silane units were studied. The measurements were performed using thin films deposited from solution. The investigated polymers have interesting semiconducting characteristics. The correlations between these characteristics and the molecular structure of the respective polymers are discussed. 相似文献
13.
Condruz Mihaela Raluca Matache Gheorghe Paraschiv Alexandru Pușcașu Cristian 《Journal of Thermal Analysis and Calorimetry》2018,133(1):443-452
Journal of Thermal Analysis and Calorimetry - Two new zinc(II) coordination compounds have been synthesized by the reaction of diazine-ring containing Schiff bases di(2-pyridyl) ketone... 相似文献
14.
Josette Olivier-Fourcade Costana Mihaela Ionica-Bousquet Pierre-Emmanuel Lippens Jean-Claude Jumas 《Hyperfine Interactions》2012,207(1-3):33-36
Due to their high storage capacity Sn-based materials are of considerable interest as negative electrode for Li-ion batteries. However the strong volume change occurring during the alloy formation strongly limits the electrochemical performances (cycle and time life). Analysis by M?ssbauer spectroscopy using model compounds (Sn, Sn-Li and transition metal-Sn alloys) shows that the volume expansion is related to the structural change from a Sn based network to a Li based network. Two types of materials are proposed here to overcome this problem: tin dispersion in an electrochemically inactive oxide matrix with buffer role to absorb volume changes or tin alloying with an inactive transition metal to minimize the volume expansion. The use of M?ssbauer spectroscopy (in situ operando mode) allows a dynamic approach which is essential to understand the fundamental causes of ageing on cycling and to define then the key issues to be solved for material’s application. 相似文献
15.
Gabriel Hancu Daniela Lupu Andreea Milan Monica Budu Enik Barabs‐Hajdu 《Biomedical chromatography : BMC》2021,35(1)
Venlafaxine (VFX) is a serotonin and norepinephrine reuptake inhibitor chiral drug used in therapy as an antidepressant in the form of a racemate consisting of R‐ and S‐VFX. The two enantiomers of VFX exhibit different pharmacological activities: R‐VFX inhibits both norepinephrine and serotonin synaptic reuptake, whereas S‐VFX inhibits only the serotonin one. R‐ and S‐VFX are metabolized in the liver to the respective R‐ and S‐O‐desmethylvenlafaxine (ODVFX), R‐ and S‐N‐desmethylvenlafaxine (NDVFX), and R‐ and S‐N,O‐didesmethylvenlafaxine (NODVFX). The pharmacological profile of ODVFX is close to that of VFX, whereas the other two chiral metabolites (NDVFX and NODVFX) have lower affinity for the receptor sites. The pharmacokinetics of the VFX enantiomers appear stereoselective, including the metabolism process. In the past 20 years, several studies describing the enantioselective analysis of R‐ and S‐VFX in pharmaceutical formulations and its chiral metabolites in biological matrices were published. These methods encompass liquid chromatography coupled with UV detection, mass spectrometry, or tandem mass spectrometry, and capillary electrophoresis. This paper reviews the published methods used for the determination of the individual enantiomers of VFX and its chiral metabolites in different matrices. 相似文献
16.
Mihaela Pascu Daniela-Elena Pascu Gina Alina Trăistaru Aurelia Cristina Nechifor Andrei A. Bunaciu Hassan Y. Aboul-Enein 《Journal of the Iranian Chemical Society》2014,11(2):315-321
The present study investigates the antioxidant activities of some Romanian plants, using different spectrophotometric methods (FRAP I, FRAP II, and CUPRAC). The plants investigated are hawthorn (Crataegus oxyacantha), bilberry (Vaccinium myrtillus L.), rosehip (Rosa canina), and chokeberries (Aronia melanocarpa). Hawthorn is used to treat a wide variety of inflammatory conditions, but the primary use is generally restricted for treating hypertension, ischemic heart disease, congestive heart failure, and arrhythmia. Investigations have proved the safe and reliable use of plant and plant extracts for treatment of cardiovascular disorders. 相似文献
17.
Mihaela Gulea Isabelle Abrunhosa Jozef Drabowicz Guillaume Grach Matthieu Hamel Serge Masson 《Phosphorus, sulfur, and silicon and the related elements》2013,188(5-6):1267-1272
Abstract A new method to prepare enantioenriched sulfinates was developed to obtain optically active ortho-methylsulfinyl(phenylphosphonates). It consists of a diastereoselective oxidation of sulfenates to sulfinates. Additionally, preliminary results concerning the synthesis of ortho-phophonylated benzylic thiol derivatives via a new P═S to P═C [1,4]-rearrangement and a first synthetic application of these compounds are also described. 相似文献
18.
19.
Taniya M. S. K. Pathiranage Dushanthi S. Dissanayake Crystal N. Niermann Yixin Ren Michael C. Biewer Mihaela C. Stefan 《Journal of polymer science. Part A, Polymer chemistry》2017,55(20):3327-3346
Semiconducting polythiophenes display electroactive properties which make them excellent candidates for applications as electroactive materials. Ability to undergo doping and to switch between different oxidation states allow tuning the chemical and physical properties of polythiophenes. Furthermore, the ability to integrate polythiophenes into copolymers, hybrid composites with metals and inorganic materials make them useful in electronic and biomedical applications. The capability to vary the properties of the final material with low production cost and high processability into thin films makes polythiophenes desirable materials for many applications. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 3327–3346 相似文献
20.
Flavie Peudru Remi Legay Jean-François Lohier Vincent Reboul Mihaela Gulea 《Tetrahedron》2012,68(44):9016-9022
A new efficient and general synthetic methodology to access γ-aminothiols was investigated and developed. 1,3-Thiazines were used as convenient precursors and were prepared by a fast microwave-assisted three-component reaction (3CR) of thioamides, aldehydes, and alkenes. The transformation of thiazines into aminothiols was achieved via a thiazinium salt hydrolysis, in three very facile steps. 相似文献