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411.
Physics of the Solid State - The influence of 0, 0.20, 0.40, 0.50, and 0.60 wt % nano-sized tin oxide (SnO2) particles on electrical conductivity fluctuation in normal and superconducting state of... 相似文献
412.
Hossein Izadi-Vasafi Faezeh Ghayoumi Samira Karbasizadeh-Esfahani Mahmood Ghafghazi 《Journal of Macromolecular Science: Physics》2020,59(5):331-343
AbstractIn this research chitosan/gelatin/starch films with a 47.5/47.5/5.0 (vol.%) composition were prepared by a solution casting method. To improve the mechanical and rheological properties of the chitosan-based films, two types of chemical crosslinkers, sodium triphosphate (STP) and calcium triphosphate (CTP), were used and the effects of these crosslinkers on the mechanical properties, swelling, water vapor transmission rate (WVTR) and the rheological-mechanical spectroscopy (RMS) of the films were investigated. For each crosslinker, two concentrations (0.05 and 0.1?wt% solutions) were used. The tensile test results showed that the samples with 0.05?wt% of STP or 0.1?wt% of CTP, had the best performance in enhancing the tensile strength and modulus of the films. The swelling tests indicated that 0.05?wt% of STP had the lowest swelling, and the performance with 0.1?wt% of CTP was also good. The results of the WVTR tests revealed that 0.05?wt% of STP and 0.1?wt% of CTP had the least and the most WVTR, respectively. Also, antibacterial tests were evaluated for the films based on an inhibition zone technique, and the results showed that the films containing the STP crosslinker has the best antibacterial activity. The RMS results indicated that the rheological properties of the films were enhanced by incorporating the crosslinkers, especially 0.1% concentration of CTP, into the film formulations. 相似文献
413.
Kharazmi Arezoo Ghorbani-Vaghei Ramin Noori Samira Alavinia Sedigheh 《Research on Chemical Intermediates》2022,48(4):1313-1329
Research on Chemical Intermediates - Recently, magnetic iron oxide nanoparticles functionalized with various organic groups increasing attention in the synthesis of the organic compounds. In this... 相似文献
414.
Clay materials, montmorillonite from Maghniya deposits (Algeria), were used as an acidic catalyst in toluene conversion. Toluene disproportionation reaction in gaseous phase was used. These clays were modified by ion exchange with uranyl ions UO22+. The surface acidity of catalysts was determined by the stepwise desorption technique (STD) of probe molecules using butylamine and ammonia. Thus, total acidity and distribution of the acidity strength were determined. The results show that materials presented an appreciable total acidity and catalytic activity in studied reaction. The acidity strength of catalysts due to UO22+ ions was kept at a temperature of 550 °C. A relationship was found between the catalytic activity and acidity strength generated by the introduction of uranyl ions in the clay structure. 相似文献
415.
The catalytic performance of exchanged Y faujasites by Ce3+, La3+, UO22+, Co2+, Sr2+, Pb2+, Tl+ and NH4+ ions were studied in a disproportionation reaction in the gaseous phase. It was shown that total acidity generated by exchanged ions is responsible of the catalytic activity. Rare earths (cerium, lanthanum and uranium) catalysts have appreciable performance and allowed one to obtain an important xylenes proportion at 400 to 450 °C. The decrease of xylenes and trimethylbenzenes proportion in studied catalysts shows the implication of xylenes in toluene disproportionation reaction. 相似文献
416.
Katayoun Marjani Mohsen Mousavi Omid Arazi Akram Ashouri Samira Bourghani Mohammad Rajabi 《Monatshefte für Chemie / Chemical Monthly》2009,33(3):1331-1336
Abstract
Sodium-hydroxide-catalyzed condensation of di-p-methyl- and di-p-methoxybenzil with acetone derivatives was investigated in methanol. Di- and trisubstituted products were obtained as cyclopentenones, while tetraaryl-substituted systems were isolated as cyclopentadienones. The structures of the products were identified by elemental analysis, infrared (IR), nuclear magnetic resonance (1H NMR), and mass spectroscopy. The solid-state structure of 4-hydroxy-3,4-bis(4-methoxyphenyl)-5,5-dimethyl-2-cyclopenten-1-one was further studied by single-crystal X-ray diffraction analysis. The title compound crystallizes in an orthorhombic space group and intermolecular O–H···O and C–H···O hydrogen bonds stabilize the crystal lattice. 相似文献417.
Sodium bicarbonate is a substance which is produced in the middle stages of the soda ash production process. In this precipitation process, carbon dioxide gas is continuously injected into the bubble column reactor which contains carbonate and bicarbonate solutions. To elucidate the key parameters affecting precipitation kinetics, an experimental study was conducted to understand nucleation and growth in conditions of industrial reactor. The composition of the solution is followed during the crystallization process by titration. Magma density is also monitored and crystal size distribution (CSD) is obtained by sieving. The method of moments was used to determine nucleation and growth rates of crystals. The nucleation and growth rate correlations for sodium bicarbonate precipitation in industrial scale were correlated by empirical power laws as B = 26.685MT0.42Δw1.31 and G = 1.381×10–4Δw1.53. The nucleation and growth rate correlations obtained in this study can be used to simulate the crystallization of sodium bicarbonate plants. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
418.
Ilaria Berruti Samira Nahim-Granados María Jesús Abeledo-Lameiro Isabel Oller María Inmaculada Polo-Lpez 《Molecules (Basel, Switzerland)》2021,26(16)
This study explores the capability of Sulfate Radical-based Advanced Oxidation Processes (SR-AOPs) for the simultaneous disinfection and decontamination of urban wastewater. Sulfate and hydroxyl radicals in solution were generated activating peroxymonosulfate (PMS) under UV-C irradiation at pilot plant scale. The efficiency of the process was assessed toward the removal of three CECs (Trimethoprim (TMP), Sulfamethoxazole (SMX), and Diclofenac (DCF)) and three bacteria (Escherichia coli, Enterococcus spp., and Pseudomonas spp.) in actual urban wastewater (UWW), obtaining the optimal value of PMS at 0.5 mmol/L. Under such experimental conditions, bacterial concentration ≤ 10 CFU/100 mL was reached after 15 min of UV-C treatment (0.03 kJ/L of accumulative UV-C radiation) for natural occurring bacteria, no bacterial regrowth was observed after 24 and 48 h, and 80% removal of total CECs was achieved after 12 min (0.03 kJ/L), with a release of sulfate ions far from the limit established in wastewater discharge. Moreover, the inactivation of Ampicillin (AMP), Ciprofloxacin (CPX), and Trimethoprim (TMP) antibiotic-resistant bacteria (ARB) and reduction of target genes (ARGs) were successfully achieved. Finally, a harmful effect toward the receiving aquatic environment was not observed according to Aliivibrio fischeri toxicity tests, while a slightly toxic effect toward plant growth (phytotoxicity tests) was detected. As a conclusion, a cost analysis demonstrated that the process could be feasible and a promising alternative to successfully address wastewater reuse challenges. 相似文献
419.
The Ground state phase diagram of the 1D spin-1/2 XXZ model in a transverse magnetic field is studied by the numerical Lanczos method. Also by computing the energy gap and different
spin-spin structure factors, quantum phase transitions in whole range of the anisotropy parameter are determined. 相似文献
420.
M. Chamanzar M. Soltani B. Momeni S. Yegnanarayanan A. Adibi 《Applied physics. B, Lasers and optics》2010,101(1-2):263-271
We introduce a hybrid photonic surface plasmon ring resonator which consists of a silicon nitride (Si3N4) dielectric traveling-wave ring resonator vertically coupled to a thin layer of metallic strip ring resonator made of Silver (Ag) on top. The cladding is assumed to be porous alumina on top of the metal layer, which provides more surface area for the adsorption of target molecules and their efficient interaction with the surface plasmon wave excited at the metal-cladding interface. Simulations show that this hybrid structure has a large refractive index sensitivity due to the excitation of surface plasmon waves and also a relatively narrow resonance linewidth due to the large quality factor of the photonic ring resonator. The Finite Element method is used to systematically design the hybrid structure and to investigate the performance of the hybrid resonator as a refractive index sensor. The proposed structure is very compact and can be implemented on a chip in an integrated platform. Thus, it can be used for lab-on-a-chip sensing applications and is capable of being spectrally and spatially multiplexed for muti-analyte sensing. 相似文献