Gamow Temperature in Tsallis and Kaniadakis Statistics

Relying on the quantum tunnelling concept and Maxwell–Boltzmann–Gibbs statistics, Gamow shows that the star-burning process happens at temperatures comparable to a critical value, called the Gamow temperature (T) and less than the prediction of the classical framework. In order to highlight the role of the equipartition theorem in the Gamow argument, a thermal length scale is defined, and then the effects of non-extensivity on the Gamow temperature have been investigated by focusing on the Tsallis and Kaniadakis statistics. The results attest that while the Gamow temperature decreases in the framework of Kaniadakis statistics, it can be bigger or smaller than T when Tsallis statistics are employed.     

High‐mobility solution‐processed zinc oxide thin films on silicon nitride

A high effective electron mobility of 33 cm² V^–1 s^–1 was achieved in solution‐processed undoped zinc oxide (ZnO) thin films. The introduction of silicon nitride (Si₃N₄) as growth substrate resulted in a mobility improvement by a factor of 2.5 with respect to the commonly used silicon oxide (SiO₂). The solution‐processed ZnO thin films grown on Si₃N₄, prepared by low‐pressure chemical vapor deposition, revealed bigger grain sizes, lower strain and better crystalline quality in comparison to the films grown on thermal SiO₂. These results show that the nucleation and growth mechanisms of solution‐processed films are substrate dependent and affect the final film structure accordingly. The substantial difference in electron mobilities suggests that, in addition to the grain morphology and crystalline structure effects, defect chemistry is a contributing factor that also depends on the particular substrate. In this respect, interface trap densities measured in high‐κ HfO₂/ZnO MOSCAPs were about ten times lower in those fabricated on Si₃N₄ substrates. (© 2014 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)

     

Current and frequency modulation characteristics for continuous-wave quantum cascade lasers at 9.06 μm

We report the characteristics of current induced frequency modulation (FM) for two continuous-wave quantum cascade lasers (QCLs) at 9.06 μm. Both the frequency tuning rate and the phase shift between intensity modulation and FM are measured at different modulation frequencies from 10 Hz to 200 kHz. The frequency tuning rate of the QCLs depends on both the modulation frequency and amplitude. The tested QCL has been used to detect ambient water vapor with wavelength modulation spectroscopy for validation with a numerical model.     

The effect of porosity on the laser induced damage threshold of TiO2 and ZrO2 single layer films

Monolayer ZrO₂ and TiO₂ films were prepared on BK7 glass by physical vapor deposition (PVD) and were subsequently annealed for 1 h at 300 °C. By using the transmission spectra of two samples and the envelope method, the refractive index dispersion and extinction coefficients have been calculated. Laser induced damage threshold (LIDT) measurement shows that despite slight differences between the extinction coefficients of the two samples, the LIDT parameter of the ZrO₂ film is greater than that of the TiO₂ film. This fact leads us to consider thermal conductivity as an important parameter for interpreting the LIDT difference. According to our theoretical analysis, as a consequence of increase in the number of thermal barriers along poorer film, its thermal conductivity, and hence LIDT, decreased, which is in agreement with our experimental results. The measured porosity of the two samples shows higher porosity for TiO₂ single layer, which is in agreement with atomic force (AFM) images. The gradual and smooth damage morphology of ZrO₂ observed in optical images implies higher thermal conductivity than TiO₂.     

Polyelectrolyte Nanocomposite Membranes Using Imidazole-Functionalized Nanosilica for Fuel Cell Applications

The preparation and characterization of a new type of nanocomposite polyelectrolyte membrane, based on DuPont Nafion/imidazole-modified nanosilica (Im-Si), for direct methanol fuel cell applications is described. Related to the interactions between the protonated imidazole groups, grafted on the surface of nanosilica, and negatively charged sulfonic acid groups of Nafion, new electrostatic interactions can be formed in the interface of Nafion and Im-Si which result in both lower methanol permeability and also higher proton conductivity. Physical characteristics of these manufactured nanocomposite membranes were investigated by scanning electron microscopy, thermogravimetry analysis, differential scanning calorimetry, Fourier transform infrared spectroscopy, water uptake, methanol permeability, and ion-exchange capacity, as well as proton conductivity. The Nafion/Im-Si membranes showed higher proton conductivity, lower methanol permeability and, as a consequence, higher selectivity parameter in comparison to the neat Nafion or Nafion/silica membranes. The obtained results indicated that the Nafion/Im-Si membranes could be utilized as promising polyelectrolyte membranes for direct methanol fuel cell applications.     

Directed Evolution of a Soluble Human IL-17A Receptor for the Inhibition of Psoriasis Plaque Formation in a Mouse Model

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Highlights? IL-17 is involved in many inflammatory diseases ? Directed evolution of IL-17A receptor results in improved IL-17A affinity ? The engineered receptors efficiently inhibit IL-17A induced cytokine secretion ? Engineered receptor promotes the recovery of psoriasis plaques in mouse model     

Non-covalently lactose imprinted polymers and recognition of saccharides in aqueous solutions

The aim of this work was to prepare lactose imprinted polymer and study of its selectivity for the recognition of different mono- and disaccharides. A series of molecularly imprinted polymers (MIPs) against lactose were synthesized and their binding properties were compared with a Blank non-imprinted polymer. Methacrylamide (MAAM) and ethylene glycol dimethacrylate were used as functional monomer and cross-linker, respectively. Dimethylsulfoxide was also applied as polymerization solvent. Different lactose:MAAM ratios were applied and optimized MIP was selected in a conventional batch adsorption study. The dissociation constant and maximum binding sites of polymer were determined using the Scatchard analysis. The selectivity of MIP for different mono- and disaccharides was also evaluated. The results indicated that the shape of cavity and orientation of functional monomers in binding sites and the spatial arrangement of hydroxyl groups in saccharide structure were responsible for the selectivity of lactose imprinted polymer.     

Novel Approach for the Synthesis of N-Substituted-4-(2-methyl-4-oxo-4H-quinazolin-3-yl)-butyramides

A simple and convenient method for the synthesis of N-substituted-4-(2-methyl-4-oxo-4H-quinazolin-3-yl)-butyramides has been reported. Several aromatic and aliphatic amide derivatives of 4-(2-methyl-4-oxo-4H-quinazolin-3-yl)-butyric acid were prepared in 60–81% yields by refluxing it with different phosphazo compounds in toluene for approximately 1 h.     

Acidic ionic liquids catalyst in homo and graft polymerization of ε-caprolactone

Biodegradable polycaprolactone was prepared by ring-opening polymerization in presence of ionic liquids as efficient, inexpensive, nontoxic, and easily handled acid catalysts. The resulting polymer exhibited good yield and inherent viscosity between 0.10 and 0.18 dL/g. The chemical structure of obtained polymer was verified by the ¹H-NMR and Fourier transform infrared spectroscopy (FT-IR) spectra. In continuation, the obtained polymer was applied to improve quality level and mechanical properties and also to reduce the hydrophilic properties of the starch, so the ring-opening polymerization of ε-caprolactone was investigated in the presence of starch hydroxyl groups as initiator and ionic liquid as catalyst. The obtained starch-grafted-polycaprolactone was verified by ¹H-NMR, FT-IR spectra, and field emission scanning electron microscopy analysis.