4H‐cyclopenta[2,1‐b:3,4‐b′]dithiophen‐4‐one (CPDTO) homopolymer with side chains on every other CPDTO

A soluble 4H‐cyclopenta[2,1‐b ;3,4‐b ′]dithiophene‐4‐one (CPDTO)‐based polymer (C₆‐PCPDTO) has been synthesized from two monomers derived from nonalkylated CPDTO and didodecyl CPDTO (C₁₂‐CPDTO). Proton NMR, thermal analysis, UV–vis absorption, cyclic voltammetry, and XRD are used to characterize the polymer in solution and film. The new polymer has an optical bandgap of 1.28 eV in film, and has strong interchain interaction in chloroform solutions. The polymer contains a significant amount of homocoupled segments. The regular segments and homocoupled CPDTO segments render the polymer highly aggregating in solution. The non‐planar homocoupled C₁₂‐CPDTO segments prevent the polymer from forming regular π‐stacks, resulting in a low SCLC hole mobility (3.88 × 10^?7 cm²V^?1s^?1). CV experiments show that C₆‐PCPDTO is stable in its oxidized and reduced states. Solar cell devices were fabricated from C₆‐PCPDTO2 :PC₆₀BM blends of different weight ratios. High PC₆₀BM loading (80% or greater) was required for the devices to show measurable efficiency, indicating that the limited π‐stacking of the polymer is not sufficient to cause effective phase separation. Further development of synthetic method is still needed to eliminate structural defects so that long‐range ordered pi‐stacking can be realized in the polymer for these applications. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 1077–1085     

Binding of a natural anthocyanin inhibitor to influenza neuraminidase by mass spectrometry

The binding of a natural anthocyanin to influenza neuraminidase has been studied employing mass spectrometry and molecular docking. Derived from a black elderberry extract, cyanidin-3-sambubiocide has been found to be a potent inhibitor of sialidase activity. This study reveals the molecular basis for its activity for the first time. The anthocyanin is shown by parallel experimental and computational approaches to bind in the so-called 430-cavity in the vicinity of neuraminidase residues 356–364 and 395–432. Since this antiviral compound binds remote from Asp 151 and Glu 119, two residues known to regulate neuraminidase resistance, it provides the potential for the development of a new class of antivirals against the influenza virus without this susceptibility.     

Weak C—H...N[triple‐bond]C hydrogen bonds in the structures of two poly(cyano)‐substituted ring systems

In benzene‐1,2,3‐tricarbonitrile, C₉H₃N₃, the packing of the two independent molecules is three‐dimensional and complex, involving inter alia bifurcated (C—H)₂...N systems from neighbouring CH groups. In [2.2]paracyclophane‐4,5,12,13‐tetracarbonitrile, C₂₀H₁₂N₄, the [2.2]paracyclophane systems display the usual distortions, namely lengthened C—C bonds and widened sp³ angles in the bridges, narrow angles in the six‐membered rings at the bridgehead atoms, and flattened boat conformations of the rings. The molecules are linked by a series of C—H...N interactions to form layers parallel to the ab plane.     

Optimization of corrugated-QWIPs for large format, high quantum efficiency, and multi-color FPAs

Previously, we demonstrated a large format 1024 × 1024 corrugated quantum well infrared photodetector focal plane array (C-QWIP FPA). The FPA has a cutoff at 8.6 μm and is BLIP at 76 K with f/1.8 optics. The pixel had a shallow trapezoidal geometry that simplified processing but limited the quantum efficiency QE. In this paper, we will present two approaches to achieve a larger QE for the C-QWIPs. The first approach increases the size of the corrugations for more active volume and adopts a nearly triangular pixel geometry for larger light reflecting surfaces. With these improvements, QE is predicted to be about 35% for a pair of inclined sidewalls, which is more than twice the previous value. The second approach is to use Fabry–Perot resonant oscillations inside the corrugated cavities to enhance the vertical electric field strength. With this approach, a larger QE of 50% can be achieved within certain spectral regions without using either very thick active layers or anti-reflection coatings. The former approach has been adopted to produce two FPAs, and the preliminary experimental results will be discussed. In this paper, we also describe using voltage tunable detector materials to achieve multi-color capability for these FPAs.     

Creep behaviour study of virgin and service exposed 5Cr–0.5Mo steel using magnetic Barkhausen emissions technique

Creep damage behaviour of water quenched 5Cr–0.5Mo steel has been studied using magnetic Barkhausen emissions (MBE) technique. The results were compared with the materials having same composition but used in service for 15 years to demonstrate the potentiality of the magnetic technique for in-situ evaluation of extent of creep damage of components. The rms voltage of magnetic Barkhausen signal for the virgin sample decreased at the initial stage of the expended creep life where new carbides are formed. As soon as the growth of the carbides took place at the expense of the smaller ones, MBE voltage started increasing due to the decrease of pinning density. However, in case of 15 years of service exposed sample, growth of carbides already took place and hence MBE voltage increased even during the initial stage of laboratory creep testing. As soon as the void started forming in the samples (both for virgin and service exposed one), the rate of increase of MBE voltage started decreasing. The formations of such cavities were observed through SEM micrograph analysis.     

Retraction Note to: Nano Pt–TiO2 for an efficient one-pot photocatalytic synthesis of quinaldines from anilines and ethanol

Research on Chemical Intermediates - This article has been retracted. Please see the Retraction Notice for more detail: https://doi.org/10.1007/s11164-020-04374-7     

Two substitutable perishable product disaster inventory systems

A disaster inventory system is considered in which two substitutable items are stored for disaster management. In the event of disaster management, a particular product may become stock-out and the situation warrants that a demand for the particular product during its stock-out period may be substituted with another available similar product in the inventory. From the utility point of view, continuous review inventory models are quite appropriate in disaster inventory management. In this paper, a continuous review two substitutable perishable product disaster inventory model is proposed and analyzed. Since the inventory is maintained for disaster management, an adjustable joint reordering policy for replenishment is adopted. There is no lead time and the replenishment is instantaneous. For this model, some measures of system performance are obtained. The stationary behavior of the model is also considered. Numerical examples are also provided to illustrate the results obtained.     

Thermal and optical properties of Cd2SnO4 thin films using photoacoustic spectroscopy

Cadmium stannate (Cd₂SnO₄) thin films were prepared by the RF magnetron sputtering technique on glass substrates with substrate temperatures of room temperature (RT), 100°C, 200°C and 300°C. Photoacoustic analyses were made to obtain the thermal diffusivity and the optical bandgap values of the Cd₂SnO₄ thin films. The change in thermal diffusivity of the films with the substrate temperature was analyzed. The optical bandgap values obtained from the photoacoustic spectroscopy were compared with the values obtained from the optical transmittance spectra. X-ray photoelectron spectroscopic (XPS) studies confirm the formation of stoichiometric films. Surface morphological studies by atomic force microscopy (AFM) revealed the crystalline nature of the films deposited at 100°C.