Investigation of the effect of aluminum doped zinc oxide (ZnO:Al) thin films by spray pyrolysis

ABSTRACT

In this study, aluminum doped zinc oxide thin films were deposited on ordinary glass substrates at the temperature of 425°C by spray pyrolysis technique for various doping concentrations of aluminum ranging from 1 to 5 at.%. The effect of dopant concentration on structural, morphological and optical properties of ZnO:Al thin films was studied. Optical band gap of the films increased with doping percentage and started to decrease from 2 at.% of dopant. The average transmittance for 2at.% ZnO:Al film is significantly increased over 90% in the visible region at 450 nm which is crucial for optoelectronic applications.     

Some Examples of Extremal Functions on the Dunkl-Type Fock Space $$F_k(\mathbb {C})$$

In this work, we recall some properties of the generalized Fock space \(F_k(\mathbb {C})\) and the Hilbert space \(H_k(\mathbb {C})\) (defined by the squared norm \(\Vert f\Vert ^2_{H_k(\mathbb {C})}:=\Vert f\Vert ^2_{F_k(\mathbb {C})}+\langle zf',f\rangle _{F_k(\mathbb {C})}\)). Next, we give the best approximation of the bounded operators \(L:F_k(\mathbb {C})\rightarrow H_k(\mathbb {C})\). As applications, we come up with some results regarding the approximate formulas for the difference operator, the Dunkl difference operator and the primitive operator.     

A Catalyst Platform for Unique Cationic (Co)Polymerization in Aqueous Emulsion

Sodium dodecyl benzene sulfonate (DBSNa) surfactants, with a polydisperse and hyperbranched structure, combined with different rare earth metal salts generate highly water‐dispersible Lewis acid surfactant combined catalysts (LASCs). This platform of new complexes promotes fast, efficient cationic polymerization of industrially relevant monomers in direct emulsion at moderate temperature. The process described here does not require high shearing, long polymerization time, or large catalyst content. It allows the reproducible generation of high‐molar‐mass homopolymers of pMOS, styrene, and isoprene, as well as random or multiblock copolymers of the latter two, in a simple and straightforward one‐pot reaction.     

Micromechanical characterization of the interphase layer in semi‐crystalline polyethylene

The interphase layer in semi‐crystalline polyethylene is the least known constituent, compared to the amorphous and crystalline phases, in terms of mechanical properties. In this study, the Monte Carlo molecular simulation results for the interlamellar domain (i.e. amorphous+ interphases), reported in (Macromolecules 2006, 39, 439–447) are employed. The amorphous elastic properties are adopted from the literature and then two distinct micromechanical homogenization approaches are utilized to dissociate the interphase stiffness from that of the interlamellar region. The results of the two micromechanical approaches match perfectly. Interestingly, the dissociated interphase stiffness lacks the common feature of positive definiteness, which is attributed to its nature as a transitional domain between two coexisting phases. The sensitivity analyses reveal that this property is insensitive to the non‐orthotropic components of the interlamellar stiffness and the uncertainties existing in the interlamellar and amorphous stiffnesses. Finally, using the dissociated interphase stiffness, its effective Young's modulus is calculated, which compares well with the effective interlamellar Young's modulus for highly crystalline polyethylene, reported in an experimental study. This satisfactory agreement along with the identical results produced by the two micromechanical approaches confirms the validity of the new information about the interphase elastic properties in addition to making the proposed dissociation methodology quite reliable when applied to similar problems. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2013 , 51, 1228–1243     

The Behavior of 3,4,5-Trimethoxybenzylidenemalononitrile Towards Alkyl Phosphites

3,4,5-Trimethoxybenzylidenemalononitrile 1 reacts with trialkyl phosphites 2a-c in the absence of solvent to give the phosphonate derivatives 4a-c . The dimeric compound 6 also was produced in the reaction with 2c . The phosphonates 8a-c were produced when compound 1 was allowed to react with dialkyl phosphites 3a-c under the same experimental conditions. A mechanism is proposed to explain the formation of compounds 4 and 6 .     

H5IO6/KI: A New Combination Reagent for Iodination of Aromatic Amines,and Trimethylsilylation of Alcohols and Phenols through in situ Generation of Iodine under Mild Conditions

A simple method for the in situ generation of iodine using H₅IO₆/KI has been developed, and its application in silylation of OH group and iodination of aromatic amines is described.     

Hyperelastic characterization of the interlamellar domain and interphase layer in semicrystalline polyethylene

The interphase layer in semicrystalline polyethylene (PE) serves as the transition between the crystalline lamellae and the amorphous domains and is recognized as the third constituent of PE. When PE undergoes large deformations, this interphase layer together with the amorphous phase behaves hyperelastically. Because of the metastable nature and nanometric size of the interphase and its intimate mechanical coupling to the neighboring crystal and amorphous domains, detailed characterization of its hyperelastic properties have eluded detailed experimental evaluation. To extract these properties, a combined algorithm is proposed based on applying the constitutive relations of an isotropic, compressible, hyperelastic continuum to the molecular dynamics simulation results of a PE stack from Lee and Rutledge (Macromolecules 2011, 3096–3108). The simulation element is incrementally deformed to a large strain, during which the stress–strain information is recorded. Assuming a neo‐Hookean model, the tensorial constitutive equation is derived. The hyperelastic parameters for the central amorphous phase, the interphase layer, and the interlamellar domain are identified with the help of the optimization notion and a set of nonnegative objective functions. The identified hyperelastic parameters for the interlamellar domain are in good agreement with the ones estimated experimentally and frequently used in the literature for the noncrystalline phase. The specifically developed sensitivity analysis indicates that the shear modulus is identified with a higher degree of certainty, in contrast to the bulk modulus. It is also revealed that the presented continuum mechanics analysis is able to capture the melting/recrystallization and rotation of crystalline chains that take place during the deformation. The evolutions of the boundaries of the hyperelastic elements are also identified concurrently with the hyperelastic parameters as the by‐product of the presented methodology. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2013 , 51, 1692–1704