Materials Literature
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This article presents results of the static and dynamic dielectric studies performed for mesogenic 4-cyanophenyl-4′-n-heptylbenzoate in the isotropic (I) and nematic (N) phases. Pretransitional phenomena are observed in the vicinity of I–N phase transition as an anomalous temperature behavior of both the static and th…
Band structure of hydrides has been studied by density functional calculations. From analysis of band structures, it is found that, similar to semiconductors, some hydrides possess open fundamental band gap, and can be classified according to the following three characteristic features. The first is based on the value…
Precession electron diffraction is used to characterize a (021) twin observed in coesite. Due to the quasi-hexagonal dimensions of coesite (monoclinic space group C12/c1 with β = 120.34°), indexing of conventional spot patterns is ambiguous and the twin law determination is impossible. With precession, spot intensitie…
Abstract Mastication of natural rubber (NR) is undertaken as a preliminary step towards the preparation of NR‐based vulcanizates, a process during which the elastomer is broken down to a homogeneous matrix of lower viscosity. Several tests and indicators are in use for characterizing the behavior of elastomers but the…
Abstract This work highlights an attempt to characterize the degree and nature of long‐chain branching (LCB) in an unknown sample of ethylene‐propylene‐diene rubber (EPDM). Two EPDM rubbers selected for this study were comparable in comonomer compositions but significantly different with respect to molar mass and the…
A sol–gel process using barium diethoxide and titanium tetraisopropoxide as the sources for Ba and Ti, respectively, was employed to synthesize BaTi 2 O 5 nanopowders and ceramics. BaTi 2 O 5 nanopowders in the range of 20–50 nm in size were obtained by calcination of the gel precursors at 650 °C. By a further firing…
A method is presented to determine the total scattering cross section of imaging gases used in low-vacuum scanning electron microscopy or environmental scanning electron microscopy. Experimental results are presented for water vapor, nitrogen gas and ambient air for primary beam electron energies between 5 and 30 keV.…
Although sol–gel‐derived magnesium‐oxide (MgO) aerogels have a wide variety of applications, mostly thin films and powders of brucite, i.e. Mg(OH) 2 aerogels, have been reported. Typically, the brucite structure is converted to the periclase form of MgO upon heat‐treatment. We report the role of acetic acid (HAc) and…
Growth and structural properties of ZnO films on (10−10) m-plane sapphire substrates by plasma-assisted molecular beam epitaxy were studied. The ZnO films were grown at a wide range of growth temperature of 100–800°C. From the x-ray diffraction θ-2θ measurements, overwhelming ZnO (10−10) reflection was confirmed in ad…
Partial discharge (PD) location is a common problem within power transformers diagnostics and is important for assessing the severity of any detected fault. The technique presented in this paper is suitable for any type of discharge signal through determination of the predominantly capacitive operating region in the f…
Abstract A series of polyurethane (PU) elastomers were prepared by the reaction of poly (ε‐caprolactone) (PCL) and 4, 4′‐diphenylmethane diisocyanate (MDI), extended with a series of chain extenders (CEs) having 2‐10 methylene units in their structure. The synthesized samples were irradiated for 50, 100, and 200 h as…
Abstract Surface modifications of nanoparticles with phospholipid polymers composed of 2‐methacryloyloxyethyl phosphorylcholine (MPC), are summarized. The MPC can be available for various polymerization methods such as conventional radical polymerization and living radical polymerization, and easily copolymerized with…
The difference in corrosion inhibition behavior of imidazole deposited on iron by two different methods has been examined using electrochemical impedance spectroscopy (EIS), x-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). Adding imidazole directly into the aqueous corrosive medium has b…
Cubic-phase zirconia nanoparticles modified with univalent surface cations have been prepared through a low-temperature solvothermal method. The obtained products were characterized by powder X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). The surface of the nanoparticles has also…
In the context of electron emission from surfaces, the area efficiency of emission (α) is defined as the ratio of the effective area of high-density emission (called the notional emission area) to the apparent area of an emitting sample as judged by its geometrical size (called the macroscopic area). For practical lar…
Coprocessing behavior of mixtures of high density polyethylene (HDPE) and deoiled cakes of Jatropha and Karanja was studied by thermogravimetric analyses under dynamic conditions in the presence of nitrogen atmosphere and compared with those of individual materials. Experiments were carried out in the temperature rang…
The utilization of coconut fibers as reinforcement in polymer composites has been increased significantly due to their low cost and high specific mechanical properties. In this paper, the mechanical properties and dynamic characteristics of a proposed combined polymer composite which consist of a polyester matrix and…
We investigated the geometric and electronic properties and doping efficiency of phosphorus-doped zinc oxide nanowires along the [0001] direction using the first-principle calculation. For isolated point defects, the substitutional and vacancy defects prefer the edge of the nanowire, the Zn interstitial defects favor…
Nanomaterials have been demonstrated as useful tools for molecular imaging, molecular diagnosis and targeted therapy in biomedical research. The main advantages of such nanomaterials are improved circulation times, precise targeting, enhancement of dissolution rates and enhanced contrast. A challenge and opportunity f…
The preparation and properties of novel calcium aluminosilicate glasses containing both nitrogen and fluorine are reported. Nitrogen increases Young's modulus and microhardness of oxide glasses by ∼25%. However, one of the major disadvantages of the use of oxynitride glasses for high‐stiffness applications is the fact…