Sharif Digital Repository

In this research, an attempt was made to improve TiO2 photo-catalyst properties, thus pure, N-Ce co-doped TiO2 thin films were prepared on glass-ceramic substrate using a sol-gel dip-coating technique. The samples were calcinated in air at 475 °C, 550°C, and 650°C for 2 h. The result of simultaneous thermal analysis (STA) and X-ray diffraction (XRD) showed that the presence of Ce in TiO2 could inhibit the phase transformation from anatase to rutile and enhance the thermal stability, and anatase was the dominant phase in N-Ce co-doped TiO2 samples. Also based on the results, the doping results in decreasing the size of TiO 2 crystallite. The results of ultra violet-visible light diffuse... 

Recent research has revealed that the security of deep neural networks that directly process 3D point clouds to classify objects can be threatened by adversarial samples. Al-though existing adversarial attack methods achieve high success rates, they do not restrict the point modifications enough to preserve the point cloud appearance. To overcome this shortcoming, two constraints are proposed. These include applying hard boundary constraints on the number of modified points and on the point perturbation norms. Due to the restrictive nature of the problem, the search space contains many local maxima. The proposed method addresses this issue by using a high step-size at the beginning of the... 

Despite brilliant properties of glass ionomer cement (GIC), its weak mechanical property poses an obstacle for its use in medical applications. The present research aims to formulate hydroxyapatite/yttria-stabilized zirconia (HA/YSZ) in the composition of GIC to enhance mechanical properties and to improve fluoride release of GIC. HA/YSZ was synthesized via a sol-gel method and characterized by applying X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photo-emission spectroscopy (XPS) and simultaneous thermal analysis (STA) along with transmission electron microscopy (TEM) methods. The synthesized nanocomposite was mixed with GIC at a fixed composition of 5.... 

In this research, a novel, rapid, and non-immune electrochemical method was used to detect cardiac troponin I (cTnI) using a double recognition approach. Amine terminus cTnI aptamers immobilized on COOH-ZnO nanoparticles (COOH-ZnONPs) modified GCE surface were applied to capture cTnI for imprinting recognition. The COOH-ZnONPs were synthesized in a biological manner. Then, the methylene blue (MB) monomers were electro-polymerized around the cTnI-aptamer complexes. Following the removal of cTnI, cavities were constructed and converted to a new aptamer and molecular imprinted polymer (MIP) hybrid receptor (aptamer/MIP/ZnONPs). FT-IR spectra, SEM images, XRD patterns, and electrochemical... 

The morphology of the perovskite layer, the effective extraction of the charge carriers, and their transport are the main factors determining the power conversion efficiency (PCE) of the perovskite solar cells (PSCs). In this work, we demonstrated that the geometric and electronic structures of the PSCs could be modified by using a conductive polymer additive in the lead (Pb) halide layer prepared by a two-step deposition method. Polypyrrole (PPy) as a conductive polymer is used in the perovskite layers which could increase the PCE of CH3NH3PbI3-xClx mixed-halide PSCs. By adding an optimized amount of PPy, PCE has been raised from 10.4 to 13.2%. PPy acts as a conductive channel facilitating... 

Perovskite solar cells have been appearing as a superior photovoltaic device owing to their high photovoltaic performance and low cost of fabrication. The formation of a compact and uniform perovskite layer with large crystal size is a significant factor to get the best device performance. In this work, polyvinylidene difluoride (PVDF) was used as a ferroelectric polymer additive to fabricate high-performance mesoporous CH3NH3PbI3-xClx mixed-halide perovskite solar cells in a sequential deposition method. Power conversion efficiency has been enhanced from 10.4 to 16.51% in an ambient atmosphere in the presence of an optimized amount of PVDF assuring continuous and smooth layers with large... 

The current study investigates the effect of polyacrylonitrile (PAN) addition on morphology and antifouling properties of poly(vinyl chloride) (PVC) asymmetric flat ultrafiltration (UF) membranes. The membranes are prepared via phase inversion method induced by immersion precipitation at different PVC/PAN blending ratio up to 40 wt% PAN. Also, membranes with blending ratio of PVC/ PAN:70/30, which showed the highest water flux and flux recovery ratio, were used for membrane preparation with 4 wt% of Polyethylene glycol (PEG) addition in four different molecular weight, 600 Da, 1,000 Da, 6,000 Da and 20,000 Da, which was used as pore former and hydrophilic polymeric additive. The performance...