Study of Temperature Dependence of Electrode–Glass Ceramic Interface Using Impedance Spectroscopy

The electrical behavior of strontium titanate borosilicate glass ceramics (SrO.TiO₂- 2SiO₂.B₂O₃) with additives K₂O, La₂O₃, CoO and Nb₂O₅ was studied by using Impedance Spectroscopy as a function of temperature and composition. An equivalent circuit model having three parallel RC's connected in series with a capacitor C₄ could represent the data well. By comparing the complex modulus plots with simulated ones and looking at the values of the time constants these RC's were attributed to represent crystalline, glassy and glass-crystal interface regions of the glass- ceramic whereas C₄ represented the glass-ceramic sample and contact electrode interface. When the glass ceramic sample contained only SrTiO₃ crystalline phase and the remaining glassy matrix, the interface capacitance showed an Arrhenius type of nature with an activation energy (0.11 ± 0.04) eV and when the glass- ceramic sample contained number of crystalline phases no clear cut trend appeared. These findings are useful in selecting suitable electrodes for applications as well as in deciding upon experimental techniques for measurement of dielectric constants of materials.     

Nonisothermal crystallization kinetics of carbon nanotubes containing segmented polyurethane elastomer

Nanocomposites of the segmented polyurethane (SPU) elastomer with different concentrations of multiwall carbon nanotubes (MWCNTs) have been prepared. Scanning electron microscopy has been used to visualize the surface morphology and distribution of the nanotubes inside the matrix. Differential scanning calorimetry has been utilized to investigate the effects of MWCNTs on the crystallization characteristics of the SPU by collecting data at four cooling rates namely 5, 10, 15, and 20°C/min in the temperature range between 200°C to ambient. The results reveal that MWCNTs act as effective nucleating agent for crystallization of the hard segment of SPU and advance the onset and peak temperatures of crystallization by 38 and 23°C, respectively. The associated enthalpy and extent of crystallization are also increased by 34%. Different crystallization kinetic parameters have been calculated using both modified Avrami and combined Ozawa‐Avrami models to suggest a three dimensional growth of crystallization of SPU and its nanocomposites. The activation energy has been calculated using Kissinger method, which indicates that activation energy decreases with increasing concentration of MWCNTs. The calorimetric results have further been correlated with thermomechanical analysis and glass transition temperature of the nanocomposites corresponding to soft segment is found to increase by 20°C. POLYM. ENG. SCI., 56:1248–1258, 2016. © 2016 Society of Plastics Engineers     

Easy,operable ionic polymer metal composite actuator based on a platinum‐coated sulfonated poly(vinyl alcohol)–polyaniline composite membrane

In this study, an electric‐stimulus‐responsive bending actuator based on a platinum (Pt)‐coated sulfonated poly(vinyl alcohol) (SPVA)–polyaniline (PANI) composite membrane was developed. The SPVA–PANI membrane was prepared by a solution casting method; it showed good electrochemical properties and an adequate ion‐exchange capacity of 1.6 mequiv/g of dry membrane. The water uptake by the membrane with 4 h of immersion time at 45 °C was found to be 425%. The SPVA–PANI composite membrane based ionic polymer metal composite (IPMC) actuator prepared by the coating of Pt metal layers on both sides of the membrane by an electroless plating process showed a good proton conductivity of 1.75 × 10^?3 S/cm. The smooth and uniform coating of Pt on both surfaces of the membrane, as indicated by scanning electron micrographs, seemed to be responsible for the slow water loss that is necessary for the long life of an IPMC actuator. The maximum water loss was 48% at 6 V for 12 min. This indicated the better performance of the IPMC membrane when an electric potential was applied. According to electromechanical characterization, the maximum tip displacement was 14.5 mm at 5.25 V. A multifinger IPMC membrane based microgripping system was developed, and it showed potential for microrobotics application. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43787.     

Bioprocess Scale-up for Acetohydroxamic Acid Production by Hyperactive Acyltransferase of Immobilized Rhodococcus Pyridinivorans

Catalysis Letters - In this study, Rhodococcus pyridinivorans cells containing hyperactive acyltransferase was immobilized on various macromolecules based-polymeric matrices and used to improve...     

A Novel Approach to Model Threshold Voltage and Subthreshold Current of Graded-Doped Junctionless-Gate-All-Around (GD-JL-GAA) MOSFETs

Silicon - This present article interprets the analytical models of central channel potential, the threshold voltage, and subthreshold current for Graded-Doped Junctionless-Gate-All-Around...     

Performance Analysis of Gate-Stack Dual-Material DG MOSFET Using Work-Function Modulation Technique for Lower Technology Nodes

Silicon - Short channel effects (SCEs) along with mobility degradation has a great impact on CMOS technology below 100 nm. These effects can be overcome by using gate and channel...     

Performance Evaluation of Stacked Gate Oxide/High K Spacers Based Gate All Around Device Architectures at 10 nm Technology Node

Silicon - In this paper, we have done performance evaluation of different Gate All Around (GAA) FET device structures using gate-oxide stacking and spacers of different materials including dual and...     

CXC Chemokine Signaling in Progression of Epithelial Ovarian Cancer: Theranostic Perspectives

Patients with epithelial ovarian cancer (EOC) are often diagnosed at an advanced stage due to nonspecific symptoms and ineffective screening approaches. Although chemotherapy has been available and widely used for the treatment of advanced EOC, the overall prognosis remains dismal. As part of the intrinsic defense mechanisms against cancer development and progression, immune cells are recruited into the tumor microenvironment (TME), and this process is directed by the interactions between different chemokines and their receptors. In this review, the functional significance of CXC chemokine ligands/chemokine receptors (CXCL/CXCR) and their roles in modulating EOC progression are summarized. The status and prospects of CXCR/CXCL-based theranostic strategies in EOC management are also discussed.