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This paper discusses the fabrication of nano ZnO filled epoxy/basalt fiber composites and investigates the effect of such hybridization on the mechanical properties of the composites. The epoxy resin is modified by the addition of ZnO nanofiller in different wt.% (1–5 wt%). The dispersion of the nanofiller within the epoxy resin is brought about by sonication technique. The composites are fabricated through wet layup followed by curing under compression molding. To ascertain the effect of resin modification, flexural and tensile strengths are evaluated. The inter‐laminar shear strength (ILSS) is determined to identify the compatibility of the ZnO nanofiller with the epoxy and the basalt fibers. The improvement in the ILSS indicates thorough wettability being achieved between all the composite components. The addition of ZnO nanofiller improved the flexural strength, while there was no remarkable improvement in the tensile strength of the ZnO modified epoxy/baslat (BEZ) composite. Maximum improvement in the strengths is observed for BEZ2 composite with 2 wt% of ZnO nanofiller. For BEZ2 composite, the flexural and tensile strength increased by about 22% and 9.78% respectively in comparison to unfilled BEZ0 composite. The ILSS for BEZ2 composite improved by 21.74% in comparison to BEZ0 composite. In addition, more than 2 wt% addition of the ZnO nanofiller resulted in the reduction of flexural, tensile and ILSS of the composite due to agglomeration. Such agglomeration resulted in the failure of the composite due to delamination, matrix cracking and fiber fracture as observed through scanning electron microscopy images of the fractured composites. [ABSTRACT FROM AUTHOR]

The research on perovskite-based photovoltaics is rapidly increasing in renewable energy, particularly in solar cell fields, as its efficiency has reached upto 25.7%. Although several efforts have been made to increase the lifetime and stability, several complicated processes are still required to be optimized, to achieve better structural and chemical stability. In this paper, perovskite material is prepared in different molar ratios, in combinations of lead iodide (PbI2) and methyl ammonium iodide (MAI) for better interdiffusion and structural ordering. All the measurements have been performed only using ITO as a bare substrate. The synchrotron source-based X-ray diffraction measurements together with SEM and UV–Vis spectroscopy were performed to understand the structural properties of perovskite films across the entire film thickness for three different molar ratios. The angular-dependent grazing incidence X-ray diffraction (GIXRD) under out-of-plane geometry can provide a better insight of structural properties at the film/air and film/ITO interfaces. Our GIXRD measurements summarizes that within the entire depth of the perovskite film, unreacted PbI2 small particles are not only laying at the bottom, but such unreacted PbI2 crystallites are also distributed along with the entire height of the perovskite film. This is completely new finding, which has been not reported yet. In combined, all these three (SEM, GIXRD, UV–Vis) states of the art techniques have not only provided the in-depth structural ordering within the entire height of the films but also reveals the surface morphology and varying optical properties of the film with varying the molar ratio's too. [ABSTRACT FROM AUTHOR]

We consider the problem of choosing the gate sizes or scale factors in a combinational logic circuit in order to minimize the total area, subject to simple RC timing constraints, and a minimum-allowed gate size. This problem is well known to be a geometric program (GP), and can be solved by using standard interiorpoint methods for small- and medium-size problems with up to several thousand gates. In this paper, we describe a new method for solving this problem that handles far larger circuits, up to a million gates, and is far faster. Numerical experiments show that our method can compute an adequately accurate solution within around 200 iterations; each iteration, in turn, consists of a few passes over the circuit. In particular, the complexity of our method, with a fixed number of iterations, is linear in the number of gates. A simple implementation of our algorithm can size a 10 000 gate circuit in 25 s, a 100 000 gate circuit in 4 min, and a million gate circuit in 40 min, approximately. For the million gate circuit, the associated GP has three million variables and more than six million monomial terms in its constraints; as far as we know, these are the largest GPs ever solved. Index Terms--Gate sizing, geometric programming (GP), large-scale optimization.

Single-mode diode lasers on an InP(001) substrate have been developed using InAs/In0.53Ga0.47As quantum dash (Qdash) active regions and etched lateral Bragg gratings. The lasers have been designed to operate at wavelengths near 2 lm and exhibit a threshold current of 65mA for a 600 lm long cavity, and a room temperature continuous wave output power per facet >5mW. Using our novel growth approach based on the low ternary In0.53Ga0.47As barriers, we also demonstrate ridge-waveguide lasers emitting up to 2.1 lm and underline the possibilities for further pushing the emission wavelength out towards longer wavelengths with this material system. By introducing experimentally the concept of high-duty-cycle lateral Bragg gratings, a side mode suppression ratio of >37 dB has been achieved, owing to an appreciably increased grating coupling coefficient of j~40 cm-1. These laterally coupled distributed feedback (LC-DFB) lasers combine the advantage of high and well-controlled coupling coefficients achieved in conventional DFB lasers, with the regrowth-free fabrication process of lateral gratings, and exhibit substantially lower optical losses compared to the conventional metal-based LC-DFB lasers. [ABSTRACT FROM AUTHOR]

The present study reports the dynamics of phase transitions at the high electron injection limit in two-dimensional layers of VO2, an archetypical strongly correlated oxide that undergoes an insulator to metal transition (IMT) at 67 °C. Prior studies to date have reported electron doping as high as ∼1021 cm−3 in epitaxial thin films and nanoparticles of VO2 through catalytic spillover and electrochemical gating in ionic liquid electrolytes, which has been shown to induce a sequential insulator-to-metal-to-insulator phase transition. With the use of two-dimensional crystalline platelets, which enable fast Li+ diffusion and out diffusion kinetics during electrochemical gating, we show that an electron density as high as 4 × 1023 cm−3 can be reversibly injected into VO2 without significant structural damage. This leads to a giant conduction modulation involving an unprecedented three-step insulator-to-metal-to-insulator-to-metal transition along with a switch in the electrical polarity from n-type to p-type due to electron doping. A unified "lattice redox model" to explain the origin of thermal-, electrochemical-, and compositional-induced IMT that involves vanadium redox-induced band filling, structural distortion, and electron correlative effects is proposed. [ABSTRACT FROM AUTHOR]