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101.
Awad A. Ibraheem M. A. Hassanain S. R. Mokhtar M. A. Zaki Zakaria M. M. Mahmoud M. El-Azab Farid 《Physics of Atomic Nuclei》2012,75(8):969-972
Microscopic folding calculations based upon the effective M3Y nucleon-nucleon interaction and the nuclearmatter densities of the interacting nuclei have been carried out to explain recently measured experimental data of the 6He+120Sn elastic scattering cross section at four different laboratory energies near the Coulomb barrier. The extracted reaction cross sections are also considered. 相似文献
102.
Joseph Bagi Suleiman Mahaneem Mohamed Ainul Bahiyah Abu Bakar Victor Udo Nna Zaida Zakaria Zaidatul Akmal Othman Abdulqudus Bola Aroyehun 《Molecules (Basel, Switzerland)》2021,26(16)
The aim of the study was to determine the chemical profile, antioxidant properties and antimicrobial activities of Heterotrigona itama bee bread from Malaysia. The pH, presence of phytochemicals, antioxidant properties, total phenolic content (TPC) and total flavonoid content (TFC), as well as antimicrobial activities, were assessed. Results revealed a decrease in the pH of bee bread water extract (BBW) relative to bee bread ethanolic extract (BBE) and bee bread hot water extract (BBH). Further, alkaloids, flavonoids, phenols, tannins, saponins, terpenoids, resins, glycosides and xanthoproteins were detected in BBW, BBH and BBE. Also, significant decreases in TPC, TFC, DPPH activity and FRAP were detected in BBW relative to BBH and BBE. We detected phenolic acids such as gallic acid, caffeic acid, trans-ferulic acid, trans 3-hydroxycinnamic acid and 2-hydroxycinnamic acid, and flavonoids such as quercetin, kaempferol, apigenin and mangiferin in BBE using high-performance liquid chromatography analysis. The strongest antimicrobial activity was observed in Klebsilla pneumonia (MIC50 1.914 µg/mL), followed by E. coli (MIC50 1.923 µg/mL), Shigella (MIC50 1.813 µg/mL) and Salmonella typhi (MIC50 1.617 µg/mL). Bee bread samples possess antioxidant and antimicrobial properties. Bee bread contains phenolic acids and flavonoids, and could be beneficial in the management and treatment of metabolic diseases. 相似文献
103.
Essam S. Zakaria Ismail M. Ali Hisham F. Aly 《Journal of colloid and interface science》2009,338(2):346-352
Magnesium titano-antimonate (MgTi5Sb2O16·12.5H2O) and cerium titano-antimonate (Ce2.7Ti5Sb2O19·15.0H2O) were synthesized as new cation exchangers using the in situ precipitation technique. Physico-chemical investigations showed different behaviors for the obtained materials. The materials have significant stability at high acid concentration and temperature. The ion exchange capacity for Cs+ in the presence of different alcoholic solvents was found to increase and generally obey the order C2H5OH > CH3OH > H2O. Diffusion coefficients (Di) and thermodynamic parameters of Cs+ exchange in both magnesium and cerium titano-antimonates in aqueous and alcoholic solutions were calculated. The swelling ratios of the materials were predicted by applying modified calculations at constant values of Di. The results showed insignificant swelling behavior in the presence of organic solvents. 相似文献
104.
Zakaria Tahraoui Habiba Nouali Claire Marichal Patrice Forler Julien Klein T. Jean Daou 《Molecules (Basel, Switzerland)》2021,26(16)
The influence of the charge compensating cation nature (Na+, Mg2+) on the water adsorption properties of LTA-type zeolites used as filler in composite materials (zeolite/polymers) was investigated. Large scale cation exchanges were performed on zeolite powder at 80 °C for 2 h using 1 M magnesium chloride (MgCl2) aqueous solutions. XRF, ICP, and EDX analyses indicate a successful cationic exchange process without the modification of the zeolite structure as shown by XRD and solid-state NMR analyses. Composite materials (granulates and molded parts) were manufactured using to extrusion and injection processes. In the case of MgA zeolite, nitrogen adsorption–desorption experiments allowed us to measure a microporous volume, unlike NaA zeolite, which is non-porous to nitrogen probe molecule. SEM and EDX analyses highlighted the homogeneous distribution of zeolite crystals into the polymer matrix. Water adsorption capacities confirmed that the trends observed in the zeolite powder samples are preserved after dragging zeolites into composite formulations. Granulates and molded parts composite samples containing the magnesium exchanged zeolite showed an increase of their water adsorption capacity up to +27% in comparison to composite samples containing the non-exchanged zeolite. The MgA composite is more promising for water decontamination applications due to its higher water adsorption properties than the NaA composite. 相似文献
105.
In this paper, we study quasi-periodic vibrational energy harvesting in a delayed self-excited oscillator with a delayed electromagnetic coupling. The energy harvester system consists in a delayed van der Pol oscillator with delay amplitude modulation coupled to a delayed electromagnetic coupling mechanism. It is assumed that time delay is inherently present in the mechanical subsystem of the harvester, while it is introduced in the electrical circuit to control and optimize the output power of the system. A double-step perturbation method is performed near a delay parametric resonance to approximate the quasi-periodic solutions of the harvester which are used to extract the quasi-periodic vibration-based power. The influence of the time delay introduced in the electromagnetic subsystem on the performance of the quasi-periodic vibration-based energy harvesting is examined. In particular, it is shown that for appropriate values of amplitudes and frequency of time delay the maximum output power of the harvester is not necessarily accompanied by the maximum amplitude of system response. 相似文献
106.
Spectral Element Discretization of the Stokes Equations in Deformed Axisymmetric Geometries
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Zakaria Belhachmi & Andreas Karageorghis 《advances in applied mathematics and mechanics.》2011,3(4):448-469
In this paper, we study the numerical solution of the Stokes system
in deformed axisymmetric geometries. In the azimuthal direction the
discretization is carried out by using truncated Fourier series,
thus reducing the dimension of the problem. The resulting
two-dimensional problems are discretized using the spectral element
method which is based on the variational formulation in primitive
variables. The meridian domain is subdivided into elements, in each
of which the solution is approximated by truncated polynomial
series. The results of numerical experiments for several geometries
are presented. 相似文献
107.
Mihoubi Z Wilcox KG Elsmere S Quarterman A Rungsawang R Farrer I Beere HE Ritchie DA Tropper A Apostolopoulos V 《Optics letters》2008,33(18):2125-2127
We report what we believe to be the first demonstration of an all-semiconductor room-temperature terahertz time domain spectrometer. An optical Stark mode-locked vertical-external-cavity surface-emitting laser with 480 fs pulses at 1044 nm was used to illuminate low-temperature-grown photoconductive antennae with 5 mum-gap bow-tie-shaped electrodes. The coherently detected spectrum has a bandwidth close to 1 THz, in which water absorption lines at 0.555 and 0.751 THz can be resolved. 相似文献
108.
The hydrodynamic and heat transfer behavior of a bed consisting of magnetic and shale oil particle admixtures under the effect
of a transverse magnetic field is investigated. The phase diagram, bed void fraction are studied under wide range of the operating
conditions i.e., gas velocity, magnetic field intensity and fraction of the magnetic particles. It is found that the range
of the stabilized regime is reduced as the magnetic fraction decreases. In addition, the bed voidage at the onset of fluidization
decreases as the magnetic fraction decreases. On the other hand, Nusselt number and consequently the heat transfer coefficient
is found to increase as the magnetic fraction decreases. An empirical equation is investigated to relate the effect of the
gas velocity, magnetic field intensity and fraction of the magnetic particles on the heat transfer behavior in the bed. 相似文献
109.
110.
K. S. Hamdan S. M. Abdullah K. Sulaiman R. Zakaria 《Applied Physics A: Materials Science & Processing》2014,115(1):63-68
We report an alternative approach to enhance the optical and electrical performance of a vanadyl 2,9,16,23-tetraphenoxy-29H,31H-phthalocyanine:poly(3hexylthiophene) (VOPcPhO:P3HT) blending system by integrating plasmonic spherical silver into an active layer of organic solar cells. Studies of the influence of the size distribution and optical properties of the silver nanoparticles were carried out using UV–Vis spectroscopy and field emission scanning electron microscopy, respectively. Electrical characteristics with and without the presence of metallic nanostructures were analyzed using J–V characteristics to observe the plasmonic effects on the performance in the VOPcPhO:P3HT organic solar cells. 相似文献