Sharif Digital Repository

Here, controlled growth of vertically aligned carbon nanotubes (VACNTs) on free-standing porous activated reduced graphene oxide (a-rGO) paper was fabricated using plasma-enhanced chemical vapor deposition method. The electrochemical performance of prepared film was investigated to provide effective electrode for 3D flexible high-performance lithium-ion batteries (LIBs) and supercapacitors. The results revealed that the prepared electrode exhibited a high specific capacitance of 347 F/g at 0.5 A/g in 1 M KOH electrolyte, 60% more than non-activated rGO-paper (218 F/g). The VACNTs on a-rGO have increased the accessible surface area and acted as efficient electrical conducting paths, which... 

TiO2 has a high bandgap energy with light absorption in the ultraviolet region making it non-efficient under visible-light. The purpose of the present work is to modify the properties of TiO2 by adding carbon and copper to its structure, in order to acquire an active nanostructure for photocatalytic oxidative desulfurization of model liquid fuel under visible light irradiation. In this regard, carbon doped TiO2 was first synthesized by a hydrothermal method, then Cu (II) were impregnated on carbon doped TiO2. The resulting photocatalysts were characterized by techniques such as XRD, N2 physisorption, SEM, TEM, DRS, EDX, PL, and FTIR. The effects of parameters including calcination... 

Metal-organic frameworks (MOFs) are a new class of porous crystalline materials being used as photocatalysts for efficient pollutant removal and environmental remediation. In this study, the TMU-32 MOF was synthesized as an effective photocatalyst for the photodegradation of tetracycline (TC) with 96% efficiency in 60 min under visible light. The high photocatalytic activity of the TMU-32 MOF is mainly due to its large specific surface area, which is beneficial for promoting both the adsorption of TC and the separation of the photoinduced charges. Moreover, its desired crystallinity makes it a semiconductor with an appropriate band gap energy. Next, a composite of the TMU-32 MOF with Fe3O4... 

Metal-organic frameworks (MOFs) are a new class of porous crystalline materials being used as photocatalysts for efficient pollutant removal and environmental remediation. In this study, the TMU-32 MOF was synthesized as an effective photocatalyst for the photodegradation of tetracycline (TC) with 96% efficiency in 60 min under visible light. The high photocatalytic activity of the TMU-32 MOF is mainly due to its large specific surface area, which is beneficial for promoting both the adsorption of TC and the separation of the photoinduced charges. Moreover, its desired crystallinity makes it a semiconductor with an appropriate band gap energy. Next, a composite of the TMU-32 MOF with Fe3O4... 

This study reports the successful fabrication of high-performance flexible binder-free lithium-ion battery anode and supercapacitor based on the synthesis of 3D hierarchical MnO2 nanoflakes (NFs) on vertically aligned carbon nanotubes (VACNTs) grown upon stainless steel (SS). The experimental results revealed that the prepared electrodes were well served as supercapacitors with a tremendous specific capacitance of MnO2 NFs VACNT/SS 1131 F/g at 0.25 A/g in 0.5 mol.L−1 Na2SO4, 518.8% more than VACNT/SS (218 F/g). Compared to other MnO2 NFs/CNT composites, as-fabricated binder-free MnO2 NFs/VACNTs electrode achieves outstanding performance with high initial discharge and charge capacities of... 

This study reports the successful fabrication of high-performance flexible binder-free lithium-ion battery anode and supercapacitor based on the synthesis of 3D hierarchical MnO2 nanoflakes (NFs) on vertically aligned carbon nanotubes (VACNTs) grown upon stainless steel (SS). The experimental results revealed that the prepared electrodes were well served as supercapacitors with a tremendous specific capacitance of MnO2 NFs VACNT/SS 1131 F/g at 0.25 A/g in 0.5 mol.L−1 Na2SO4, 518.8% more than VACNT/SS (218 F/g). Compared to other MnO2 NFs/CNT composites, as-fabricated binder-free MnO2 NFs/VACNTs electrode achieves outstanding performance with high initial discharge and charge capacities of... 

Here, we report 3D hierarchical SnO2 nanowire (NW) core-amorphous silicon shell on free-standing carbon nanotube paper (SnO2@a-Si/CNT paper) as an effective anode for flexible lithium-ion battery (LIB) application. This binder-free electrode exhibits a high initial discharge capacity of 3020 mAh g-1 with a large reversible charge capacity of 1250 mAh g-1 at a current density of 250 mA g-1. Compared to other SnO2 NW or its core-shell nanostructured anodes, the fabricated SnO2@a-Si/CNT structure demonstrates an outstanding performance with high mass loading (∼5.9 mg cm-2), high areal capacity (∼5.2 mAh cm-2), and large volumetric capacity (∼1750 mAh cm-3) after 25 cycles. Due to the... 

In the bone tissue engineering field (BTE), it is of significant importance to develop bioactive multifunctional scaffolds with enhanced osteoconductivity, osteoinductivity, and antibacterial properties required for lost bone tissue regeneration. In this work, a bioactive glass-ceramic scaffold was manufactured via a novel polymer-derived ceramics (PDC) manufacturing method. To gain antibacterial properties, the silver ions were incorporated in controlled amount along with other precursors in the PDC processing stage. Microstructural and structural properties of the fabricated silicate-phosphate glass-ceramic scaffold were evaluated by scanning electron microscopy (SEM) equipped with energy... 

In the bone tissue engineering field (BTE), it is of significant importance to develop bioactive multifunctional scaffolds with enhanced osteoconductivity, osteoinductivity, and antibacterial properties required for lost bone tissue regeneration. In this work, a bioactive glass-ceramic scaffold was manufactured via a novel polymer-derived ceramics (PDC) manufacturing method. To gain antibacterial properties, the silver ions were incorporated in controlled amount along with other precursors in the PDC processing stage. Microstructural and structural properties of the fabricated silicate-phosphate glass-ceramic scaffold were evaluated by scanning electron microscopy (SEM) equipped with energy... 

Let R be a ring and f(x1,..., xn) be a polynomial in noncommutative indeterminates x1,..., xn with coefficients from ℤ and zero constant. The ring R is said to be an f-ring if f(r1,..., rn) = 0 for all r1,..., rn of R and a virtually f-ring if for every n infinite subsets X1,..., Xn (not necessarily distinct) of R, there exist n elements r1 ∈ X1,...,rn ∈ Xn such that f(r1,..., rn) = 0. Let R* be the 'smallest' ring (in some sense) with identity containing R such that Char (R) = Char (R*). Then denote by ZR the subring generated by the identity of R* and denote by f̄R the image of f in ZR [x1,..., xn] (the ring of polynomials with coefficients in ZR in commutative indeterminates x1,..., xn).... 

To exert the optimum effect, the chemical exchange process to boron isotope separation was investigated. In this enrichment method the distillation of dimethyl ether-boron trifluoride complex, which was one of the most efficient industrial methods for purification of isotope boron-10, was optimized. In chemical exchange process of boron isotopes separation two chemical reactions occur. The first one is the decomposition reaction that is an endothermic reaction. The second one is the exchange reaction that is a pyrogenic reaction. With increasing temperature, the decomposition reaction is speeded while the exchange reaction is slowed down. Affecting on both decomposition and exchange... 

We have recently introduced a high-level extension for stochastic activity networks (SANs) called coloured stochastic activity networks (CSANs). CSANs have several distinguishing properties, which make them quite appropriate for modeling and evaluation of software performance and dependability. CSANs have introduced a construct called coloured place for data manipulation. A coloured place holds a list of tokens of a userdefined token type. CSAN models can be evaluated by state space analysis techniques or discrete-event simulation. However, their state spaces will become very large, even for a small CSAN model. For efficient evaluation of these models by state space analysis methods, we will... 

Stochastic activity networks (SANs) are a stochastic generalization of Petri nets. SAN models have been used to evaluate a wide range of systems and are supported by several modeling tools. We have introduced object stochastic activity networks (OSANs) to overcome some restrictions of these models. OSANs integrate the concepts of object-orientation into SAN models. Elements of OSANs and their submodels are defined as classes. OSANs are more appropriate that most other objectoriented or high-level extensions of Petri nets for application on software systems. In this paper, we will present the definitions, behavior and an example of OSAN models. The objectorientation of OSANs and the...