Afshin Maleki | University of Tehran (original) (raw)
Working about powder metallurgy
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Catalysis Communications, Jan 1, 2008
Alumina supports were prepared by solvothermal method of a mixed solution of toluene and butan-1-... more Alumina supports were prepared by solvothermal method of a mixed solution of toluene and butan-1-ol for various chi/gamma phase compositions and the Pt/Al2O3 catalyst was prepared by the incipient wetness impregnation technique. The catalysts were evaluated in the carbon monoxide oxidation. Increasing amount of %chi phase in the alumina supports has roughly the same BET surface area. The different alumina supports were affected on the Pt dispersion on alumina. The pure chi alumina and pure gamma alumina supports had the same effect of catalyst activity. In the various chi/gamma phase compositions, it was found that Pt dispersion and catalyst activity are lower than pure gamma and chi phases for alumina support with 10% chi. The alumina supports with 30–70% chi gave higher dispersion and activity than pure phase and 10% chi support.
Journal of The American Ceramic Society, Jan 1, 1991
Nanocrystalline Al203 thin films (50 nm in thickness) have been synthesized by rf reactive sputte... more Nanocrystalline Al203 thin films (50 nm in thickness) have been synthesized by rf reactive sputtering deposition and subjected to annealing at temperatures ranging from 800° to 1200°C. TEM analysis indicated that the as-deposited alumina films contained both amorphous phase and metastable γ phase. Structural texture evolved in the films annealed at 800°C for 24 h; the texture had a [00l] preferred orientation and occurred along the {400} and {440} planes of γ Al203, . In the films annealed a t 1200°C for 2h, nucleation and concurrent anomalous grain growth of α-Al203took place in a fine-grained, polycrystalline γ-Al203 matrix. The anomalously grown γ-AL2O3 grains were primarily [0001]-oriented single crystals with grain sizes varying from 3 to 15 pm, while the γ-Al2O3 matrix had an average grain size of 50 nm. The γ-Al2O3 matrix was also strongly textured along the [001] axis and exhibited a heavily faulted, layered micro-structure. Most of these layers were oriented along the {220} crystallographic planes. Periodic superstructure was identified in the layered γ- Al2O3. The formation of layered structure in γ- Al2O3 is attributable to the change of stacking sequence of atomic layers along the {220} orientations. An atomic model is presented to explain the formation of layered structure in γ- Al2O3. The nucleation of α- Al2O3 appears to occur along the {220} crystallographic planes of γ- Al2O3. The explosive grain growth of α- Al2O3 during the γαphase transformation is explained by a mechanism involving interface boundary migration and lattice epitaxy. The orientation relationships between γ- and α- Al2O3 are determined.
Journal of Clinical Pharmacy and Therapeutics, Jan 1, 1998
To evaluate and compare the efficacy and safety of fenofibrate and lovastatin in patients with ty... more To evaluate and compare the efficacy and safety of fenofibrate and lovastatin in patients with type IIa or IIb hyperlipidaemia. One hundred patients entered this single-centre, open, comparative trial. After 2 months of diet therapy, 33 patients (16 with type IIa and 17 with type IIb hyperlipidaemia) were randomized to treatment for 3 months with a single daily 300 mg dose of fenofibrate or 20 mg of lovastatin. After 3 months of drug therapy, fenofibrate and lovastatin produced significant reductions in levels of total cholesterol and low-density lipoprotein cholesterol in type IIa hyperlipidaemia. In type IIb, the levels of total cholesterol were significantly decreased by both drugs, but only lovastatin significantly reduced low-density lipoprotein cholesterol in these patients. High-density lipoprotein cholesterol levels were significantly increased by lovastatin in type IIa and fenofibrate in type IIb. Fenofibrate decreased total triglyceride levels in both types of hyperlipidaemia significantly more effectively than lovastatin. The most important and commonly observed adverse effects in the fenofibrate group were dermatological events (three patients), myalgia (two patients) and asymptomatic increase in aminotransferase values (nine patients), while in the lovastatin group cardiovascular events (five patients) were the most common. All five patients had coronary heart disease at baseline. In general terms, both drugs were well tolerated. Comparison between fenofibrate and lovastatin after 3 months of drug therapy in both types IIa and IIb hyperlipidaemia demonstrated that both drugs produced similar reductions in levels of total cholesterol and low-density lipoprotein cholesterol. However, fenofibrate decreased total triglyceride levels in both types of hyperlipidaemia, more effectively than lovastatin. Thus, fenofibrate is suitable for both primary hypercholesterolaemia and combined hyperlipidaemia.
Catalysis Communications, Jan 1, 2008
Alumina supports were prepared by solvothermal method of a mixed solution of toluene and butan-1-... more Alumina supports were prepared by solvothermal method of a mixed solution of toluene and butan-1-ol for various chi/gamma phase compositions and the Pt/Al2O3 catalyst was prepared by the incipient wetness impregnation technique. The catalysts were evaluated in the carbon monoxide oxidation. Increasing amount of %chi phase in the alumina supports has roughly the same BET surface area. The different alumina supports were affected on the Pt dispersion on alumina. The pure chi alumina and pure gamma alumina supports had the same effect of catalyst activity. In the various chi/gamma phase compositions, it was found that Pt dispersion and catalyst activity are lower than pure gamma and chi phases for alumina support with 10% chi. The alumina supports with 30–70% chi gave higher dispersion and activity than pure phase and 10% chi support.
Journal of The American Ceramic Society, Jan 1, 1991
Nanocrystalline Al203 thin films (50 nm in thickness) have been synthesized by rf reactive sputte... more Nanocrystalline Al203 thin films (50 nm in thickness) have been synthesized by rf reactive sputtering deposition and subjected to annealing at temperatures ranging from 800° to 1200°C. TEM analysis indicated that the as-deposited alumina films contained both amorphous phase and metastable γ phase. Structural texture evolved in the films annealed at 800°C for 24 h; the texture had a [00l] preferred orientation and occurred along the {400} and {440} planes of γ Al203, . In the films annealed a t 1200°C for 2h, nucleation and concurrent anomalous grain growth of α-Al203took place in a fine-grained, polycrystalline γ-Al203 matrix. The anomalously grown γ-AL2O3 grains were primarily [0001]-oriented single crystals with grain sizes varying from 3 to 15 pm, while the γ-Al2O3 matrix had an average grain size of 50 nm. The γ-Al2O3 matrix was also strongly textured along the [001] axis and exhibited a heavily faulted, layered micro-structure. Most of these layers were oriented along the {220} crystallographic planes. Periodic superstructure was identified in the layered γ- Al2O3. The formation of layered structure in γ- Al2O3 is attributable to the change of stacking sequence of atomic layers along the {220} orientations. An atomic model is presented to explain the formation of layered structure in γ- Al2O3. The nucleation of α- Al2O3 appears to occur along the {220} crystallographic planes of γ- Al2O3. The explosive grain growth of α- Al2O3 during the γαphase transformation is explained by a mechanism involving interface boundary migration and lattice epitaxy. The orientation relationships between γ- and α- Al2O3 are determined.
Journal of Clinical Pharmacy and Therapeutics, Jan 1, 1998
To evaluate and compare the efficacy and safety of fenofibrate and lovastatin in patients with ty... more To evaluate and compare the efficacy and safety of fenofibrate and lovastatin in patients with type IIa or IIb hyperlipidaemia. One hundred patients entered this single-centre, open, comparative trial. After 2 months of diet therapy, 33 patients (16 with type IIa and 17 with type IIb hyperlipidaemia) were randomized to treatment for 3 months with a single daily 300 mg dose of fenofibrate or 20 mg of lovastatin. After 3 months of drug therapy, fenofibrate and lovastatin produced significant reductions in levels of total cholesterol and low-density lipoprotein cholesterol in type IIa hyperlipidaemia. In type IIb, the levels of total cholesterol were significantly decreased by both drugs, but only lovastatin significantly reduced low-density lipoprotein cholesterol in these patients. High-density lipoprotein cholesterol levels were significantly increased by lovastatin in type IIa and fenofibrate in type IIb. Fenofibrate decreased total triglyceride levels in both types of hyperlipidaemia significantly more effectively than lovastatin. The most important and commonly observed adverse effects in the fenofibrate group were dermatological events (three patients), myalgia (two patients) and asymptomatic increase in aminotransferase values (nine patients), while in the lovastatin group cardiovascular events (five patients) were the most common. All five patients had coronary heart disease at baseline. In general terms, both drugs were well tolerated. Comparison between fenofibrate and lovastatin after 3 months of drug therapy in both types IIa and IIb hyperlipidaemia demonstrated that both drugs produced similar reductions in levels of total cholesterol and low-density lipoprotein cholesterol. However, fenofibrate decreased total triglyceride levels in both types of hyperlipidaemia, more effectively than lovastatin. Thus, fenofibrate is suitable for both primary hypercholesterolaemia and combined hyperlipidaemia.