Effect of molar ratio and calcination temperature on particle size of CeO2/-Al2O3 nanocomposites prepared via reverse micelle process
A porous composite of cerium oxide and gama aluminum oxide pigments were prepared via sol-gel processing controlled within reverse micelles of nonionic surfactant Triton X-114 in cyclohexane. The precursor in heated at several calcinations temperature between 823 to 1123K. This process includes three steps. In the first step of preparation the ceria sol was prepared. In the second step, cyclohexane was mixed with surfactant and distilled water by the addition of ceria sol. In final step, nano gama aluminum oxide was fluently injected into the mixture. The precursor micellar ceria/-alumina sol with different molar ratio was mechanically stirred to form a homogeneous suspension. The mixture was washed with some organic solvent. Also, the effect of different molar ratio of Ce:Al on the crystallization was studied. The study of X-ray diffraction XRD, transmission electron microscopy TEM, scanning electron microscopy SEM, temperature programmed reduction TPR and N2 adsorption/desorption isotherm suggested that well crystalline nanosized pigments are obtained. The product pigments posses mesoporosity with broadly distributed pores between 20 to 45 nm diameters. Surface area increases by increasing the calcination temperature. Also, the particle size of the pigments decreases with an increasing in molar ratio of Ce:Al.
the effect of explicit teaching of metacognitive vocabulary learning strategies on recall and retention of idioms
چکیده ندارد.15 صفحه اول
effect of seed priming and irrigation regimes on yield,yield components and quality of safflowers cultivars
این مطالعه در سال 1386-87 در آزمایشگاه و مزرعه پژوهشی دانشگاه صنعتی اصفهان به منظور تعیین مناسب ترین تیمار بذری و ارزیابی اثر پرایمینگ بر روی سه رقم گلرنگ تحت سه رژیم آبیاری انجام گرفت. برخی از مطالعات اثرات سودمند پرایمینگ بذر را بر روی گیاهان مختلف بررسی کرده اند اما در حال حاضر اطلاعات کمی در مورد خصوصیات مربوط به جوانه زنی، مراحل نموی، عملکرد و خصوصیات کمی و کیفی بذور تیمار شده ژنوتیپ های م...
Synthesis of Polybutadiene Nanoparticles via Emulsion Polymerization: Effect of Reaction Temperature on the Polymer Microstructure, Particle Size and Reaction Kinetics
Polybutadiene nanoparticles were synthesized via batch emulsion polymerization of butadiene in the presence of potassium persulfate, disproportionate rosinate potassium cation and t-dodecyl mercaptane as initiator, emulsifier and chain transfer agent, respectively. Polymerization reaction was performed at different temperatures (60, 70 and 80 °C). Conversion was measured at the various time int...متن کامل
EFFECT OF CALCINATION TEMPERATURE OF THE KAOLIN AND MOLAR Na2O/SiO2 ACTIVATOR RATIO ON PHYSICAL AND MICROSTRUCTURAL PROPERTIES OF METAKAOLIN BASED GEOPOLYMERS
Metakaolinite-based geopolymer has been synthesized at about 25 °C from metakaolin which has been calcined in different temperatures (600-900 °C) and different Na2O/SiO2 ratio activator (0.3-1.1). Compressive strength and microstructure of cement pastes after 7-28 days curing at ambient temperature were measured. Compressive strength tests on the samples showed that the sample made with calcine...متن کامل
effect of postharvest application of chitosan and calcium chloride on decay and quality attributes of sweet cherry
چکیده ندارد.15 صفحه اول
Three types of solvents with different polarity (cyclohexane, toluene and benzene), a nonionic surfactant Span 40 were used to prepare strontium aluminate (SrAl2O4) spinel nanoparticles by a reverse micelle method. The structure of SrAl2O4 nanoparticles was characterized by X-ray diffraction (XRD). The morphology and size of the synthesized materials were studied using field emission scanning e...متن کامل
دوره 9 شماره 2
صفحات 109- 116
تاریخ انتشار 2016-05-01
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