A polymer electrolyte containing ionic liquid for possible applications in photoelectrochemical solar cells

Various iodide ion conducting polymer electrolytes have been studied as candidate materials for fabricating photoelectrochemical (PEC) solar cells and energy storage devices. In this study, enhanced ionic conductivity values were obtained for the ionic liquid tetrahexylammonium iodide containing polyethylene oxide (PEO)-based plasticized electrolytes. The analysis of thermal properties revealed the existence of two phases in the electrolyte, and the conductivity measurements showed a marked conductivity enhancement during the melting of the plasticizer-rich phase of the electrolyte. Annealed electrolyte samples showed better conductivity than nonannealed samples, revealing the existence of hysteresis. The optimum conductivity was shown for the electrolytes with PEO:salt = 100:15 mass ratio, and this sample exhibited the minimum glass transition temperature of 72.2 °C. For this optimum PEO to salt ratio, the conductivity of nonannealed electrolyte was 4.4 × 10⁻⁴ S cm⁻¹ and that of the annealed sample was 4.6 × 10⁻⁴ S cm⁻¹ at 30 °C. An all solid PEC solar cell was fabricated using this annealed electrolyte. The short circuit current density (I _SC), the open circuit voltage (V _OC), and the power conversion efficiency of the cell are 0.63 mA cm⁻², 0.76 V, and 0.47% under the irradiation of 600 W m⁻² light.     

Spin squeezing and quantum correlations

We discuss the notion of spin squeezing considering two mutually exclusive classes of spin-s states, namely, oriented and non-oriented states. Our analysis shows that the oriented states are not squeezed while non-oriented states exhibit squeezing. We also present a new scheme for construction of spin-s states using 2s spinors oriented along different axes. Taking the case of s=1, we show that the ‘non-oriented’ nature and hence squeezing arise from the intrinsic quantum correlations that exist among the spinors in the coupled state.     

Neural expression and post-transcriptional dosage compensation of the steroid metabolic enzyme 17β-HSD type 4

Background  

Steroids affect many tissues, including the brain. In the zebra finch, the estrogenic steroid estradiol (E₂) is especially effective at promoting growth of the neural circuit specialized for song. In this species, only the males sing and they have a much larger and more interconnected song circuit than females. Thus, it was surprising that the gene for 17β-hydroxysteroid dehydrogenase type 4 (HSD17B4), an enzyme that converts E₂ to a less potent estrogen, had been mapped to the Z sex chromosome. As a consequence, it was likely that HSD17B4 was differentially expressed in males (ZZ) and females (ZW) because dosage compensation of Z chromosome genes is incomplete in birds. If a higher abundance of HSD17B4 mRNA in males than females was translated into functional enzyme in the brain, then contrary to expectation, males could produce less E₂ in their brains than females.     

Binding Modes of Thioflavin T on the Surface of Amyloid Fibrils Studied by NMR

The mechanism for the interaction of thioflavin T (ThT) with amyloid fibrils at the molecular level is not known. Here, we used ¹H NMR spectroscopy to determine the binding mode of ThT on the surface of fibrils from lysozyme and insulin. Relayed rotating‐frame Overhauser enhancements in ThT were observed, indicating that the orientation of ThT is orthogonal to the fibril surface. Importantly, the assembly state of ThT on both surfaces is different. On the surface of insulin fibrils, ThT is oligomeric, as indicated by rapid ¹H spin‐lattice relaxation rate in the rotating frame (R_1ρ), presumably due to intermolecular dipole–dipole interactions between ThT molecules. In contrast, ThT on the surface of lysozyme fibrils is a monomer, as indicated by slower ¹H R_1ρ. These results shed new light into the mechanism for the enhancement of ThT fluorescence and may lead to more efficient detectors of amyloid assemblies, which have escaped detection by ThT in monomer form.     

An experimental test of the scaling prediction for the spatial distribution of water during the drying of colloidal films

A Peclet number, Pe, for the drying of colloidal films can be used as a predictor of the uniformity of water concentration in the direction normal to the film. Uniform drying is predicted to occur when Pe < 1, whereas with , a layer of packed particles is expected to develop above a more dilute layer. Routh and Zimmerman have more recently proposed that the particle concentration gradient between the packed and dilute layers, , will scale as . Here, this scaling relation is tested experimentally with magnetic resonance profiling data obtained from waterborne colloidal films dried under conditions to yield a range of Pe. It is found that increases with Pe but scales as . This disagreement with the prediction can be attributed to an underestimate of Pe when there are greater non-uniformities of drying, because of an unquantified slowing down of the evaporation rate.     

Theory of sheath in a collisional multi-component plasma

The aim of this brief report is to study the behaviour of sheath structure in a multi-component plasma with dust-neutral collisions. The plasma consists of electrons, ions, micron size negatively charged dust particles and neutrals. The sheath-edge potential and sheath width are calculated for collisionally dominated sheath. Comparison of collisionless and collisionally dominated sheath are made.     

Effect of nanoporous alumina filler on conductivity enhancement in PEO9(MgClO4)2 polymer electrolyte: a 1H NMR study

Ionic conductivity, differential scanning calorimetry (DSC), and ¹H nuclear magnetic resonance (NMR) measurements have been performed on (PEO)₉Mg(ClO₄)₂ and (PEO)₉Mg(ClO₄)₂ + Al₂O₃ (neutral, nanoporous) polymer electrolyte systems. It is observed that the conductivity enhances due to the presence of filler up to 15 wt.% and then decreases. The NMR results are consistent with the idea that the conductivity enhancement is mainly due to the increase in chain mobility and ionic mobility of the solid polymer electrolyte caused by increased amorphocity of the electrolyte due to the presence of filler. DSC results also demonstrate that the fraction of the amorphous phase has increased due to the addition of the filler.     

Analysis of a shielded TE011 mode composite dielectric resonator for stable frequency reference

Analysis of a TE₀₁₁ mode composite sapphire-rutile dielectric resonator has been carried out to study the temperature variation of resonance frequency, close to the Cs atomic clock hyperfine frequency of 9.192 GHz. The complementary behavior of dielectric permittivity with temperature of the composite has been exploited to obtain the desired turning point in the resonant frequency. The frequency of the composite structure is found to be independent of the shield diameter beyond four times the puck diameter.     

Aspects of an inventory control study

A case study for the design of a spare parts inventory control system is described. The main emphasis is given to the problems of applying and tailoring forecasting and inventory control theory to suit the needs of a particular problem. In the main, well established methods were used and these are not described in detail. New developments arising in the course of the study have been described elsewhere.