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31.
32.
Masoud Salavati-Niasari Faezeh Soofivand Ali Sobhani-Nasab Maryam Shakouri-Arani Masood Hamadanian Samira Bagheri 《Journal of Materials Science: Materials in Electronics》2017,28(20):14965-14973
In this work, CdTiO3 nanoparticles were synthesized through reaction between Cd(CH3COO)2.2H2O, Ti(OC4H9)4, trimesic acid as a new chelating agent and ethanol as solvent by Pechini sol–gel method. X-ray diffraction (XRD) patterns showed that CdTiO3 nanostructures have rhombohedral structure with diameter of about 35.61 nm. The structure, morphology and size of CdTiO3 nanoparticles were characterized by FT-IR, XRD, SEM and EDAX. The optical properties of the products were studied by DRS. Based on the results of experiments, it was found that temperature and time of calcination, pH and the solvent of reaction are important parameters for formation of CdTiO3 nanoparticles. Utilizing trimesic acid (benzene-1,3,5-tricarboxylic acid) as a new chelating agent for preparation of CdTiO3 nanostructures was initiative of this work. 相似文献
33.
Samira Khalili 《Chemical engineering science》2008,63(5):1330-1341
This work focuses on the analysis of HIV infection dynamics during the initial stages of infection when the viral load is low and random fluctuations may have a significant effect on the dynamics of the disease. Deterministic models that describe the expected progress of the infection cannot be employed to predict the probability of infection establishment at the primary stage. Consequently, stochastic simulations are used to determine the probability of successful infection in an average patient. A stochastic model based on Gillespie's algorithm is derived which includes mutant species and employed to determine the sensitivity of HIV infection to different treatment strategies such as single therapy and combination therapy with various efficacy values. The effect of treatment latency on virus clearance probability is also investigated. 相似文献
34.
Carlos H. Herrera-Mendez Samira Becila Gerald Coulis Miguel A. Sentandreu Laurent Aubry Ahmed Ouali 《Food research international (Ottawa, Ont.)》2010,43(1):356-363
Thrombin/antithrombin III (AT-III) proteolytic system is well known for its function in blood coagulation. Thrombin is expressed in skeletal muscle but nothing is known about the presence of AT-III in the tissue. In postmortem muscle this system has been and is still totally ignored. We therefore successfully attempted to purify AT-III from bovine skeletal muscle and characterized the purified protein (identified as AT-III by N-ter sequencing and mass spectrometry finger print) for its physicochemical and inhibitory properties. As the human blood serpin, muscle AT-III is thermolabile and stable only at alkaline pH (pH 9–10). The muscle serpin inhibits strongly thrombin in a heparin dependent manner and trypsin. Phosphatidylserine (PS) externalization demonstrated in the present work suggested that prothrombin can be activated to thrombin through binding of the activator complex on the external PS groups. PS externalization is concomitant with shrinkage of muscle fibers indicating that muscle cells are engaged in the cell death program known as apoptosis few minutes after death. We then discussed the potential role of this proteolytic system in postmortem apoptosis development as well as in the control of low voltage electrical stimulation efficiency. 相似文献
35.
Djahida Lerari Sophie Peeterbroeck Samira Benali Ahmed Benaboura Philippe Dubois 《Polymer International》2010,59(1):71-77
Nanocomposites of poly(methyl methacrylate) (PMMA) filled with 3 wt% of modified natural Algerian clay (AC; montmorillonite type) were prepared by either in situ polymerization of methyl methacrylate initiated by 2,2′‐azobisisobutyronitrile or a melt‐mixing process with preformed PMMA via twin‐screw extrusion. The organo‐modification of the AC montmorillonite was achieved by ion exchange of Na+ with octadecyldimethylhydroxyethylammonium bromide. Up to now, this AC montmorillonite has found applications only in the petroleum industry as a rheological additive for drilling muds and in water purification processes; its use as reinforcement in polymer matrices has not been reported yet. The modified clay was characterized using X‐ray diffraction (XRD), which showed an important shift of the interlayer spacing after organo‐modification. The degree of dispersion of the clay in the polymer matrix and the resulting morphology of nanocomposites were evaluated using XRD and transmission electron microscopy. The resulting intercalated PMMA nanocomposites were analysed using thermogravimetric analysis and differential scanning calorimetry. The glass transition temperature of the nanocomposites was not significantly influenced by the presence of the modified clay while the thermal stability was considerably improved compared to unfilled PMMA. This Algerian natural montmorillonite can serve as reinforcing nanofiller for polymer matrices and is of real interest for the fabrication of nanocomposite materials with improved properties. Copyright © 2009 Society of Chemical Industry 相似文献
36.
Band gap grading is able to improve the performance of CIGS solar cells. In order to get a better understanding of the parameters influencing the effect of a grading, a closed form analytical expression of the current density is derived. The advantages and drawbacks of this analytical expression with respect to numerical simulation results are assessed. The analytical analysis has limited validity due to restrictions on the absorption characteristic and on the recombination in the space charge layer. Nevertheless it leads to good results, it has the advantage of being faster than numerical simulations and it clarifies the interrelation of the meaningful parameters. 相似文献
37.
Multivalent defects, e.g. double donors/acceptors or amphoteric defects, are important in materials used in solar cell production in general and in chalcopyrite materials in particular. We extended our thin film solar cell simulation software scaps to enable the simulation of multivalent defects with up to five different charge states; the algorithms presented are however able to simulate an arbitrary number of possible charge states. The presented solution method avoids numerical inaccuracies caused by the subtraction of two almost equal numbers.This new modelling facility is afterwards used to investigate the consequences of the multivalent character of defects for the simulation of chalcopyrite based solar cells. 相似文献
38.
This article investigates the mechanical, morphological, and thermal properties of poly(vinyl chloride) (PVC) and low‐density polyethylene (LDPE) blends, at three different concentrations: 20, 50, and 80 wt% of LDPE. Besides, composite samples that were prepared from PVC/LDPE blend reinforced with different date palm leaf fiber (DPLF) content, 10, 20, and 30 wt%, were also studied. The sample in which PVC/LDPE (20 wt%/80 wt%) had the greatest tensile strength, elongation at break, and modulus. The good thermal stability of this sample can be seen that T10% and T20% occurred at higher temperatures compared to others blends. DPLF slightly improved the tensile strength of the polymer blend matrix at 10 wt% (C10). The modulus of the composites increased significantly with increasing filler content. Ageing conditions at 80°C for 168 h slightly improved the mechanical properties of composites. Scanning electron microscopic micrographs showed that morphological properties of tensile fracture surface are in accordance with the tensile properties of these blends and composites. Thermogravimetric analysis and derivative thermogravimetry show that the thermal degradation of PVC/LDPE (20 wt%/80 wt%) blend and PVC/LDPE/DPLF (10 and 30 wt%) composites took place in two steps: in the first step, the blend was more stable than the composites. In the second step, the composites showed a slightly better stability than the PVC/LDPE (20 wt%/80 wt%) blend. Based on the above investigation, these new green composites (PVC/LDPE/DPLF) can be used in several applications. J. VINYL ADDIT. TECHNOL., 25:E88–E93, 2019. © 2018 Society of Plastics Engineers 相似文献
39.
Polyvinyl chloride (PVC) was modified via substitution reaction with 2‐aminothiazole and ethyl 2‐aminothiazole‐4‐carboxylate separately in the absence and in presence of silver (AgNPs) or copper (CuNPs) nanoparticles, using metal salts as precursors, in 3% (w/w) with respect to PVC. The functionalized PVC‐nanocomposites have been characterized via FTIR, 1HNMR spectroscopic analyses, in addition to the morphological investigation such as scanning (SEM) and transmission electron microscopy (TEM). Spectral data confirmed the introduction of the thiazole (ester) to the PVC backbone. TEM analysis showed that the sizes of the AgNPs and CuNPs have fallen in the range of 10–30 nm and 30–50 nm for the prepared nanocomposites, respectively. Evaluating the photostability of modified nanocomposites was estimated by following the extent of discoloration for UV‐irradiated samples colorimetrically in accordance with the irradiation time. The antimicrobial activity of the modified nanocomposites was explored against three Gram+ve bacteria (Bacillus subtilis, Staphylococcus aureus, and Streptococcus faecalis), three Gram‐ve bacteria (Escherichia coli, Neisseria gonorrhoeae, and Pseudomonas aeruginosa), and two fungi (Candida albicans and Aspergillus flavus). Aminothiazole (ester)‐functionalized PVC exhibited significant antimicrobial efficiencies against the investigated pathogens. However, incorporation of AgNPs or CuNPs to the modified PVC enhanced their inhibitory effect against the microorganisms under investigation. J. VINYL ADDIT. TECHNOL., 25:E137–E146, 2019. © 2018 Society of Plastics Engineers 相似文献
40.
Mohammad Ghashghaee Samira Shirvani Mehdi Ghambarian Ali Eidi 《Petroleum Science and Technology》2019,37(16):1910-1916
A two-stage thermocatalytic upgrading process using a novel catalyst was investigated to produce light olefins and liquid fuels from fuel oil. The upgraded oil from the first thermal stage demonstrated lower viscosity and higher crackability compared to the virgin feedstock. In the next step, the vapor-phase catalytic cracking of the upgraded fraction was implemented over a novel nanoporous composite catalyst, characterized by the XRD, FTIR, NH3- TPD, and N2 physisorption techniques. In total, more than 55?wt% of light olefins, particularly propylene (25.5?wt%) together with 25.4?wt% and 32.5?wt% of gasoline and diesel fuel were obtained in this process. 相似文献