Search for: lanthanum-compounds
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    On the rate of oxidation of co on La2O3 doped NiO/Al2O3 catalysts: An artificial neural network approach

    , Article Reaction Kinetics and Catalysis Letters ; Volume 85, Issue 2 , 2005 , Pages 347-353 ; 01331736 (ISSN) Ardakani, S. J ; Gobal, F ; Sharif University of Technology
    The rate constants of the oxidation of CO on a number of pure and La 2O3 doped NiO/Al2O3 solid catalysts were correlated with the mole percent of dopant, calcinations temperature, surface area, pore volume and pore mouth diameter by an artificial neural network simulator. The cross validation method had to be used due to the scarcity of the data. A three-layer network with 3 nodes in the hidden layer was found to simulate the system well. © Akadémiai Kiadó, Budapest. All rights reserved  

    Interface effect on the formation of a dipole of screw misfit dislocations in an embedded nanowire with uniform shear eigenstrain field

    , Article European Journal of Mechanics, A/Solids ; Volume 51 , May–June , 2015 , Pages 154-159 ; 09977538 (ISSN) Shodja, H. M ; Enzevaee, C ; Gutkin, M. Y ; Sharif University of Technology
    Elsevier Ltd  2015
    The critical condition for the generation of a screw misfit dislocation dipole (MDD) at the interface between a nanowire (NW) with uniform shear misfit strain and its surrounding unbounded matrix within surface/interface elasticity theory is of particular interest. The analysis is carried out using the complex potential variable method. It is shown that the critical radius of the NW corresponding to the onset of the MDD generation decreases with the increase in the uniform shear eigenstrain inside the NW as well as when the stiffness of the NW increases with respect to the matrix. The critical radius strongly depends on the non-classical interface parameter. Comparison is made with classical... 

    The effect of particle size on the structural, magnetic and electrical properties of La0.9Ba0.1MNO3 manganite samples

    , Article Phase Transitions ; Volume 92, Issue 11 , 2019 , Pages 949-959 ; 01411594 (ISSN) Shogh, S ; Eshraghi, M ; Sharif University of Technology
    Taylor and Francis Ltd  2019
    In this work, the magnetic and transport properties of micro and nanometer-sized samples of La0.9Ba0.1MnO3 manganite have been studied. The temperature variation of ac susceptibility of the nanometer-sized sample shows one transition at high temperature (265 K). On the contrary, the ac susceptibility of the micrometer-sized sample shows two transitions with a high-temperature transition occurring at 240 K and low-temperature transition around 100 K. The high-temperature transition corresponds to the paramagnetic-ferromagnetic (PM–FM) transition (Tc) and is independent of frequency, while the low-temperature transition is frequency-dependent and shifts toward high temperatures by increasing... 

    Substrate and device pattern dependence of the thermal crosstalk in y Ba 2Cu 3O 7-δ transition edge bolometer arrays

    , Article IEEE Transactions on Applied Superconductivity ; Volume 16, Issue 4 , 2006 , Pages 1953-1958 ; 10518223 (ISSN) Bozbey, A ; Fardmanesh, M ; Schubert, J ; Banzet, M ; Sharif University of Technology
    Using YBa 2Cu 3O 7-δ (YBCO) thin films, pulsed laser deposited on 1-mm-thick LaAlO 3 or SrTiO 3 substrates, we made 4 × 1 pixel arrays of transition edge bolometers with separations between neighboring pixels ranging from 40 μm to 170 μm for testing purposes. We investigated the effects of the YBCO film thickness (200 and 400 nm), substrate material, and back-etching of the substrate, on the crosstalk between the pixels of the arrays. The investigation was based on the analysis of the voltage response of the dc current biased bolometers versus the modulation frequency of a near-infrared laser source. We observed that the bolometer arrays made of 400-nm-thick films had less interpixel thermal... 

    Numerical investigation of the effect of sprue base design on the flow pattern of aluminum gravity casting

    , Article Defect and Diffusion Forum ; Volume 344 , October , 2013 , Pages 43-53 ; 10120386 (ISSN) ; 9783037859049 (ISBN) Baghani, A ; Bahmani, A ; Davami, P ; Varahram, N ; Shabani, M. O ; Fisher D. J ; Sharif University of Technology
    Effects of sprue base size and design on flow pattern during aluminum gravity casting have been investigated by employing different sprue base sizes and using computational fluid dynamics (CFD). Calculations was carried out using SUTCAST simulation software based on solving Navier-Stokes equation and tracing the free surface using SOLA-VOF algorithm. Flow pattern was analyzed with focusing on streamlines and velocity distribution in sprue base, runner and in-gate. Increasing well size was produced a vortex flow at the bottom of sprue base which increased the surface velocity of liquid metal in runner. Using a rather big sprue well could eliminate vena contracta, but in-gate velocity was... 

    Nontoxic concentrations of PEGylated graphene nanoribbons for selective cancer cell imaging and photothermal therapy

    , Article Journal of Materials Chemistry ; Volume 22, Issue 38 , 2012 , Pages 20626-20633 ; 09599428 (ISSN) Akhavan, O ; Ghaderi, E ; Emamy, H ; Sharif University of Technology
    Reduced graphene oxide nanoribbons functionalized by amphiphilic polyethylene glycol (rGONR-PEG) were applied to attach arginine-glycine-aspartic acid (RGD)-based peptide and cyanine dye 3 (cy3) for targeting ανβ3 integrin receptors on human glioblastoma cell line U87MG and its selective fluorescence imaging, respectively. The rGONR-PEG suspension with a concentration of 100 μg mL -1 showed ∼14 and 2.4-fold higher near infrared (NIR) absorption at 808 nm than GONR (with dimensions of ∼80 nm × 1 μm) and rGO-PEG sheets (with lateral dimensions of ∼2 μm), respectively. The rGONR-PEG-cy3-RGD exhibited highly efficient NIR photothermal therapy performance (concentrations ≥1.0 μg mL-1 resulted in... 

    Dual-sensitive hydrogel nanoparticles based on conjugated thermoresponsive copolymers and protein filaments for triggerable drug delivery

    , Article ACS Applied Materials and Interfaces ; Volume 10, Issue 23 , 17 May , 2018 , Pages 19336-19346 ; 19448244 (ISSN) Ghaffari, R ; Eslahi, N ; Tamjid, E ; Simchi, A ; Sharif University of Technology
    American Chemical Society  2018
    In this study, novel hydrogel nanoparticles with dual triggerable release properties based on fibrous structural proteins (keratin) and thermoresponsive copolymers (Pluronic) are introduced. Nanoparticles were used for curcumin delivery as effective and safe anticancer agents, the hydrophobicity of which has limited their clinical applications. A drug was loaded into hydrogel nanoparticles by a single-step nanoprecipitation method. The drug-loaded nanoparticles had an average diameter of 165 and 66 nm at 25 and 37 °C, respectively. It was shown that the drug loading efficiency could be enhanced through crosslinking of the disulfide bonds in keratin. Crosslinking provided a targeted release... 

    Integer-forcing message recovering in interference channels

    , Article IEEE Transactions on Vehicular Technology ; Volume 67, Issue 5 , May , 2018 , Pages 4124-4135 ; 00189545 (ISSN) Azimi Abarghouyi, S. M ; Hejazi, M ; Makki, B ; Nasiri Kenari, M ; Svensson, T ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2018
    In this paper, we propose a scheme referred to as integer-forcing message recovering (IFMR) to enable receivers to recover their desirable messages in interference channels. Compared to the state-of-the-art integer-forcing linear receiver (IFLR), our proposed IFMR approach needs to decode considerably less number of messages. In our method, each receiver recovers independent linear integer combinations of the desirable messages each from two independent equations. We propose an efficient polynomial-time algorithm to sequentially find the equations and integer combinations with maximum rates and analyze its complexity. We evaluate the performance of our scheme and compare the results with the... 

    HTS YBCO resonator configuration with a coplanar optimized flux concentrator strongly coupled to RF squid

    , Article IEEE Transactions on Applied Superconductivity ; Volume 28, Issue 4 , 2018 ; 10518223 (ISSN) Qaderi, F ; Shanehsazzadeh, F ; Mazdouri, B ; Fardmanesh, M ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2018
    We developed a novel magnetic coupling module, formed of a monolayer superconducting flux concentrator that is integrated with a coplanar resonator, strongly coupled to high-temperature superconducting radio frequency superconducting quantum interference device (SQUID). Three types of resonators, including a long stripline resonator between the input loop and the pick-up loop of the flux concentrator, a complementary split ring resonator, and a spiral shape inside the input loop, are explored. The resonance quality factor of different patterns of these three types of the resonators, as well as their coupling to the SQUID, is evaluated using finite-element-method simulations. Several readout... 

    Delivery of hydrophobic anticancer drugs by hydrophobically modified alginate based magnetic nanocarrier

    , Article Industrial and Engineering Chemistry Research ; Volume 57, Issue 3 , 2018 , Pages 822-832 ; 08885885 (ISSN) Pourjavadi, A ; Amin, S. S ; Hosseini, H ; Sharif University of Technology
    American Chemical Society  2018
    Since most of the anticancer drugs have low solubility in water, the clinical use of them is limited unless by some modification the solubility increases or the drug is carried with a soluble compartment. To solve this problem, we prepared a magnetic nanocarrier with a hydrophobic surface based on oleic acid chains in which hydrophobic drug molecules such as doxorubicin hydrochloride (DOX) and paclitaxel (PTX) are easily adsorbed onto the surface. Since the drug molecules are physically adsorbed on the surface, large amounts of DOX (282 mg·g-1) and PTX (316 mg·g-1) were immobilized onto the nanocarrier. Then, the surface of the drug loaded magnetic core was covered by a smart pH-sensitive... 

    Improving oxygen electrodes by infiltration and surface decoration

    , Article 16th International Symposium on Solid Oxide Fuel Cells, SOFC 2019, 8 September 2019 through 13 September 2019 ; Volume 91, Issue 1 , 2019 , Pages 1413-1424 ; 19386737 (ISSN); 9781607688747 (ISBN) Hendriksen, P. V ; Khoshkalam, M ; Tong, X ; Tripkovic, D ; Faghihi Sani, M. A ; Chen, M ; High-Temperature Energy, Materials, and Processes; SOFC Society of Japan; The Electrochemical Society ; Sharif University of Technology
    Electrochemical Society Inc  2019
    For improving competitiveness of SOEC/SOFC-technology it is desirable to reduce the temperature of operation down towards 500 oC - 600 oC. This requires improvement of the oxygen electrode such that this does not limit performance. Here, we report results on modifying various back-bone type oxygen electrodes via infiltration of materials targeting a surface decoration with Pr-oxide or Pr,Ni,Cu-oxides. Different composite back-bone electrodes (based on micron-sized particles) were investigated; La0.6Sr0.4Co0.2Fe0.8O3/Ce0.9Gd0.1O2, (LSCF/CGO), La0.6Sr0.4FeO3 (LSF), and LaNi0.6Fe0.4O3/Ce0.9Gd0.1O2 (LNF/CGO). Marked performance improvements could be achieved with the infiltration, including a... 

    A pH-sensitive carrier based-on modified hollow mesoporous carbon nanospheres with calcium-latched gate for drug delivery

    , Article Materials Science and Engineering C ; Volume 109 , 2020 Asgari, S ; Pourjavadi, A ; Hosseini, S. H ; Kadkhodazadeh, S ; Sharif University of Technology
    Elsevier Ltd  2020
    A novel nanocarrier based-on hollow mesoporous carbon nanospheres (HMCNs) with primary amines on its surface, a large cavity, and good hydrophilicity was synthesized by a hydrothermal reaction. The primary amine functionalities on the mesoporous carbon were used as the initiation sites for growing poly (epichlorohydrin) (PCH) chains. The chlorine groups in the side chain of PCH were replaced with imidazole as the pendant groups. Calcium chloride (CaCl2) was applied as a capping agent. The coordination bonding was formed between pendant imidazole groups and calcium ions. Doxorubicin (DOX) was selected as a model of hydrophilic anticancer drug and was loaded onto the nanocarrier and released... 

    Improving oxygen incorporation rate on (La0.6Sr0.4)0.98FeO3-δ via Pr2Ni1-xCuxO4+δ surface decoration

    , Article Journal of Power Sources ; Volume 457 , May , 2020 Khoshkalam, M ; Tripković, Ð ; Tong, X ; Faghihi Sani, M. A ; Chen, M ; Hendriksen, P. V ; Sharif University of Technology
    Elsevier B. V  2020
    Insufficient electrocatalytic activity for oxygen reduction/evolution in lanthanum strontium ferrite (LSF) perovskites at temperatures below 700 °C, limits the utilization of these Co-free oxides as oxygen electrodes for intermediate-temperature solid oxide fuel/electrolysis cells (SOFC/SOEC). Marked performance improvement is here reported by decorating the surface with Pr2Ni1-xCuxO4 catalyst particles. Infiltrating porous LSF electrodes with aqueous nitrates solutions containing Pr, Ni and Cu, targeting the compositions Pr2Ni0.7Cu0.3O4 and Pr2Ni0.6Cu0.4O4, significantly reduces the polarization resistance at 650 °C from 0.98 Ω cm2 to 0.16 Ω cm2 and 0.13 Ω cm2 respectively. Electrical... 

    High-efficiency microwave absorber based on carbon Fiber@La0.7Sr0.3MnO@NiO composite for X-band applications

    , Article Ceramics International ; Volume 47, Issue 14 , 2021 , Pages 20438-20446 ; 02728842 (ISSN) Fang, Y ; Li, H ; Niaz Akhtar,, M ; Shi, L ; Sharif University of Technology
    Elsevier Ltd  2021
    Carbon fiber (CF) as a multifunctional material with superb performance in aviation industry has serious drawback such as impedance mismatch which restricted the capability of using it as microwave absorber materials. In this research, a novel hierarchical carbon fiber@La0.7Sr0.3MnO@NiO (CF/LS/N) composite was facilely and successfully synthesized via sol-gel and subsequent hydrothermal reactions. The structural, morphological, magnetic and electromagnetic behavior of the composite were precisely evaluated via XRD, FESEM, XPS, VSM and VNA analysis. According to the systematic evaluation results, the synergistic positive effect of adding NiO nanoparticles is revealed in improving the... 

    Natural polymers decorated mof-mxene nanocarriers for co-delivery of doxorubicin/pCRISPR

    , Article ACS Applied Bio Materials ; Volume 4, Issue 6 , 2021 , Pages 5106-5121 ; 25766422 (ISSN) Rabiee, N ; Bagherzadeh, M ; Jouyandeh, M ; Zarrintaj, P ; Saeb, M. R ; Mozafari, M ; Shokouhimehr, M ; Varma, R. S ; Sharif University of Technology
    American Chemical Society  2021
    A one-pot and facile method with assistance of high gravity was applied for the synthesis of inorganic two-dimensional MOF-5 embedded MXene nanostructures. The innovative inorganic MXene/MOF-5 nanostructure was applied in co-delivery of drug and gene, and to increase its bioavailability and interaction with the pCRISPR, the nanomaterial was coated with alginate and chitosan. The polymer-coated nanosystems were fully characterized, and the sustained DOX delivery and comprehensive cytotoxicity studies were conducted on the HEK-293, PC12, HepG2, and HeLa cell lines, demonstrating acceptable and excellent cell viability at both very low (0.1 μg.mL-1) and high (10 μg·mL-1) concentrations. The... 

    Viral infected cells reveal distinct polarization behavior; a polarimetric microscopy analysis on HSV infected Vero and HeLa cells

    , Article Journal of Quantitative Spectroscopy and Radiative Transfer ; Volume 262 , 2021 ; 00224073 (ISSN) Amiri, S ; Abedini, M ; Badieyan, S ; Vaezjalali, M ; Akhavan, O ; Sasanpour, P ; Sharif University of Technology
    Elsevier Ltd  2021
    The optical polarization properties of virus-infected cells have been measured, analyzed, and compared with the uninfected cells. In this regard, Vero and HeLa cells have been used as the host for Herpes simplex viruses (HSV). By using polarization microscopy imaging technique, the Mueller matrix images of infected and uninfected cells have been recorded. Through image processing and further analysis, the polarization properties of host cells are compared with their infected ones. For quantitative analysis, the multispectral Mueller matrix transformation (MMT) parameters (A and b) are calculated to identify the microstructural differentiations between uninfected and infected cells by HSV.... 

    Al-doped Li7La3Zr2O12 garnet-type solid electrolytes for solid-state Li-Ion batteries

    , Article Journal of Materials Science: Materials in Electronics ; Volume 32, Issue 5 , 2021 , Pages 6369-6378 ; 09574522 (ISSN) Ashuri, M ; Golmohammad, M ; Soleimany Mehranjani, A. R ; Faghihi Sani, M ; Sharif University of Technology
    Springer  2021
    Cubic phase Li7La3Zr2O12 (LLZO) is a promising solid electrolyte for next-generation Li-ion batteries. In this work, the combustion sol–gel technique is used to prepare an Al-doped LLZO solid electrolyte. The crystal structure is investigated, and the cubic phase is confirmed. Densification properties were investigated using SEM and optical dilatometry. The densification of the Al-doped sample takes place in two stages through two different shrinkage rates. Using 0.25 mol Al-dopant 94% relative density is achieved at 1100 °C. The effect of Al-doping on electrochemical properties is investigated in detail using AC impedance spectroscopy. The result indicates that the optimum concentration of... 

    Electrical behavior of nano-polycrystalline (La1-yK y)0.7Ba0.3MnO3 manganites

    , Article Journal of Magnetism and Magnetic Materials ; Volume 322, Issue 21 , November , 2010 , Pages 3255-3261 ; 03048853 (ISSN) Mazaheri, M ; Akhavan, M ; Sharif University of Technology
    We present a study of the structural and electrical behavior of nano-polycrystalline mixed barium and alkali substituted lanthanum-based manganite, (La1-yKy)0.7Ba0.3MnO 3 with y=0.00.3. The samples were synthesized by the polymerization complex solgel method. The powder X-ray diffraction (XRD) data of the samples show a single-phase character with R3c space group. The magnetic and electrical transport properties of the nano-polycrystalline samples have been investigated in the temperature range 50300 K and a magnetic field up to 10 kOe. The metalinsulator transition temperature Tp of all the samples decreased with potassium doping, and also, it increased slightly with the application of... 

    Metal-nonmetal transition in the copper-carbon nanocomposite films

    , Article Physica B: Condensed Matter ; Volume 405, Issue 18 , Jan , 2010 , Pages 3949-3951 ; 09214526 (ISSN) Ghodselahi, T ; Vesaghi, M. A ; Shafiekhani, A ; Ahmadi, M ; Panahandeh, M ; Heidari Saani, M ; Sharif University of Technology
    We prepared Cu nanoparticles in a-C:H thin films by co-deposition of RF-sputtering and RF-PECVD methods at room temperature. By increasing Cu content in these films a nonmetalmetal (NM) transition is observed. This transition is explainable by the power law of percolation theory. The critical metal content is obtained 56% and the critical exponent is obtained 1.6, which is larger than the exponent for 2 dimension systems and smaller than the one for 3 dimension systems. The electrical conductivity of dielectric samples was explained by tunneling. Activation tunneling energy that was obtained from temperature dependence of electrical resistivity correlates with near infrared absorption peak... 

    The effect of chemical pressure in rutheno-cuprates

    , Article Physica C: Superconductivity and its Applications ; Volume 470, Issue 4 , 2010 , Pages 285-290 ; 09214534 (ISSN) Nikseresht, N ; Khajehnezhad, A ; Hadipour, H ; Akhavan, M ; Sharif University of Technology
    We have studied the effect of negative chemical pressure in the RuGd 1.5(Ce 0.5-xPr x)Sr 2Cu 2O 10-δ with Pr content of 0.0 ≤ x ≤ 0.2. This is also investigated using the bond length results obtained from the Rietveld refinement analysis. The c parameter and cell volume increase with x for 0.0 ≤ x ≤ 0.15. The width of the resistivity transition also increases with Pr concentration, indicating higher inhomogeneity and oxygen deficiency. The difference in the ionic valences of Pr 3+,4+ and Ce 4+ causing different hole doping, the difference in the ionic radii, and oxygen stoichiometry affect the superconducting transition. The magnetoresistance shows a cusp around 135 K which lies between the...