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111.
Cover Picture: Viologen‐Templated Arrays of Cucurbit[7]uril‐Modified Iron‐Oxide Nanoparticles (Chem. Eur. J. 12/2015) 下载免费PDF全文
112.
Maha Benzarti-GhédiraHaikel Hrichi Nejmeddine JaballahRafik Ben Chaâbane Mustapha MajdoubHafedh Ben Ouada 《Physica B: Condensed Matter》2012,407(7):1051-1054
The opto-electronic properties of native poly(p-phenylene vinylene) (PPV) were tuned by the confinement of the π-conjugation and the incorporation of a sulphur group as a spacer in order to obtain a blue-green emitting polymer (PPVS). The energy band gap of the PPVS thin film has been measured by UV-vis absorption spectroscopy and evaluated to 2.87 eV. Current-voltage characteristics and impedance spectroscopy measurements performed on sandwich structures [ITO/PPVS/Al] are used to elucidate the conduction mechanisms. The static electrical characterisations showed a space charge limited conduction (SCLC) and a conductivity with low power frequency behaviour characteristic of a hopping transport in disordered materials. The impedance spectra can be discussed in terms of an equivalent circuit model designed as a parallel resistor RP and capacitor CP network in series with a resistor RS. We extract numerical values of these parameters by fitting experimental data. Their evolution with bias voltages has shown that the SCLC mechanism is characterised by an exponential trap distribution. 相似文献
113.
Alaaeddin Alsbaiee Mustapha St. Jules Rachel L. Beingessner Jae-Young Cho Takeshi Yamazaki Hicham Fenniri 《Tetrahedron letters》2012,53(13):1645-1651
Rosette nanotubes (RNTs) are discrete nanostructures self-assembled from a guanine–cytosine hybrid motif (G∧C) under aqueous conditions. These materials have substantial design flexibility and a range of applications, which are partly attributed to their diverse surface functionalization. Given the potential for interesting properties resulting from a metal-RNT construct, here we describe an oxorhenium-functionalized RNT. More specifically, we present the synthesis of a twin G∧C motif expressing the mercaptoacetyl triglycine (MAG3) ligand. We then examine the chelation reaction of the MAG3 with ReOCl3(PPh3)2 and self-assemble the resulting ReO-MAG3-G∧C conjugate into RNTs under DMSO and aqueous conditions. 相似文献
114.
Tewfik Bouchaour Frédérick Roussel Jean-Marc Buisine Xavier Coqueret Mustapha Benmouna Ulrich Maschke 《Liquid crystals》2013,40(4):487-491
The thermophysical properties of mixtures of poly (2-phenoxyethylacrylate) and 4-cyano-4′-pentyl-biphenyl, 5CB, are investigated using polarizing optical microscopy (POM) and differential scanning calorimetry (DSC). The polymer has a molar mass M w = 181 000 g mol -1 the low molecular mass liquid crystal exhibits a nematic to isotropic transition at 35.3°C and crystallizes below 23°C. The phase diagram exhibits miscibility gaps in certain regions of temperature and composition where coexisting nematic and isotropic phases are found. From a practical point of view when considering the electro-optical applications of these systems, it proves to be useful to know precisely the amount of small liquid crystal molecules dissolved in the polymer matrix and the concentration of polymer in the nematic phase. The former quantity has a mechanical impact due to a plasticizing effect, an optical impact since it changes the polymer refractive index, while the polymer in the nematic phase shifts the transition temperatures influencing the electro-optical response of the liquid crystal. The present work addresses these important aspects using POM and DSC. 相似文献
115.
Salima Atlas Mustapha Raihane Gregory B. Kharas Peter G. Hendrickson Hamid Kaddami Mourad Arous 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(12):997-1010
Copolymerization of fluorine ring-substituted 2-phenyl-1,1-dicyanoethenes, RC6H3CH?C(CN)2 (R is 2,3-F,F, 2,4-F,F, 2,5-F,F, 2,6-F,F, and 4-CF3) with 4-fluorostyrene were prepared in the presence of a radical initiator (ABCN) at 70°C. The composition of the copolymers was calculated from nitrogen analysis, and the copolymers were characterized by IR, 1H and 13C-NMR, GPC, DSC, and TGA. The monomer reactivity ratios for 4-fluorostyrene (M1), r1 = 0.6 and 2-(2,4-difluorophenyl)-1,1-dicyanoethene (M2), r2 = 0 were determined from Fineman-Ross plot. The order of relative reactivity (1/r1) for difluoro-substituted monomers is 2,4-F,F (0.31) > 2,3-F,F (0.25) > 2,5-F,F (0.22) > 2,6-F,F (0.10). DSC curves showed that the copolymers were amorphous with high T g in comparison with that poly(4-fluorostyrene) indicating a substantial decrease in chain mobility of the copolymer due to the high dipolar character of the trisubstituted ethylene monomer units. From the thermogravimetric analysis, the copolymers began to degrade in the range 214–260°C. The copolymer of 4-fluorostyrene and 2-(2,4-difluorophenyl)-1,1-dicyanoethene and poly(4-fluorostyrene) were dielectrically characterized in the range 25–200°C. The dominating relaxation process detected in both materials was the α-relaxation, associated with the dynamic glass transition. The relationship polarity-permittivity was discussed. 相似文献
116.
Redouane Khaoulaf Mustapha Ezzaafrani Abdelaziz Ennaciri Mohammed Harcharras Francesco Capitelli 《Phosphorus, sulfur, and silicon and the related elements》2013,188(11):1367-1376
Abstract Infrared and Raman spectra of dipotassium zinc bis(dihydrogendiphosphate) dihydrate, K2Zn(H2P2O7)2 .2H2O have been collected and interpreted using factor group analysis. Noncoincidence of the Raman and infrared spectra bands confirms a centrosymmetric structure for K2Zn(H2P2O7)2 .2H2O previously investigated by X-ray structural study, as well as the joint appearance of νas POP and νs POP point to a bent POP configuration. 相似文献
117.
Hilbert transform and continuous wavelet transform are combined to form an algorithm for the analysis of a single fringe pattern with open or closed fringes. Only one recorded fringe pattern is needed to extract the phase information. A second π/2 phase shifted fringe pattern should first be generated from the other using Hilbert transform to superpose numerically the spatial carrier. Several phase extraction techniques are conceived to demodulate fringe patterns. In this paper, the wavelet technique is used to obtain the required phase distribution. The algorithm offers an advantage that it is appropriate when the spatial carrier is impossible to be added experimentally. Finally, a simulation was carried out to validate the algorithm, giving good results. 相似文献
118.
Abdellah Aghraz Ambrogina Albergamo Qada Benameur Andrea Salvo Mustapha Larhsini Mohamed Markouk 《Natural product research》2020,34(1):63-70
AbstractAim of this study was to evaluate polyphenols and major and trace elements of Cladanthus arabicus and Bubonium imbricatum, along with their in vitro antibacterial activity against six multidrug resistant Enterobacteriaceae (Escherichia coli S33/16, E. coli S34/16, Proteus mirabilis S32/16, Klebsiella pneumoniae S12/16, Enterobacter cloacae S5/16, and Salmonella sp S12/14). UV spectrophotometry, ultra-high-performance liquid chromatography coupled to mass spectrometry and inductively coupled plasma mass spectrometry were used to evaluate total polyphenol content, quali-quantitative profile of single polyphenols and inorganic elements of the extract. The antibacterial activity was investigated by standard methods. Twelve polyphenols were identified in both plants and these were more concentrated in B. imbricatum than C. arabicus extracts. High levels of minerals, essential trace elements and tolerable levels of heavy metals (Cd, As and Pb) were found. Furthermore, the extracts showed also a strong in vitro antibacterial activity, particularly versus E. coli S33/16 (MIC, 0.125?mg ml?1). 相似文献
119.
Selective Detection of Dopamine in Presence of Ascorbic Acid by Use of Glassy‐Carbon Electrode Modified with Amino‐β‐Cyclodextrin and Carbon Nanotubes 下载免费PDF全文
Aymen Gaied Nejmeddine Jaballah Moncef Tounsi Mohamed Braiek Nicole Jaffrezic‐Renault Mustapha Majdoub 《Electroanalysis》2014,26(12):2747-2753
A glassy carbon electrode modified with per‐6‐amino‐β‐cyclodextrin (β‐CDNH2) and functionalized single‐walled carbon nanotubes (SWCNT‐COOH) was elaborated. This structure was investigated for the detection of dopamine acid (DA) in presence of ascorbic acid (AA). The sensor behavior was studied by cyclic voltammetry, square wave voltammetry and electrochemical impedance spectroscopy. The analysis results show that the electrode modification with CD derivative improves the sensitivity and selectivity of the DA recognition; the electrochemical response was further improved by introduction of SWCNT‐COOH. The sensor shows good and reversible linear response toward DA within the concentration range of 7×10?7–10?4 M with a detection limit of 5×10?7 M. 相似文献
120.
Mustapha Raïssouli 《Linear and Multilinear Algebra》2019,67(2):213-220
Let T and S be two self-adjoint positive invertible operators of a complex Hilbert space H. In this paper, we investigate some inequalities involving the quadratic forms of the weighted arithmetic and harmonic means of T and S. Application for operator entropies is also discussed. 相似文献