Pore growth in heavy ion-irradiated PET foils using a constructed ECE unit

A well performance Electrolytic Controlled Etching (ECE) unit has been designed and constructed in our laboratory. Low electric field strength of few volts and a 2 kHz wave signals has been applied across the electrodes that confined the 9 and 12 μm thick PET foils in the ECE unit. PET foils were exposed to fission fragments (FF_S) using ²⁵²Cf source. The dependence of different measurable parameters such as FF_S fluence (Φ), applied voltage (V), etching temperature (T) and etching concentration (C) on both track etch rate (V _T) and breakthrough time (T _B) have extensively been studied using the FF_S-irradiated PET foils. Various empirical relationships connecting the results of the present work have been extracted. Moreover, the constructed ECE technique has proven to be an encouraged time saving method in the development of trusting measurements comparing with others that might involve expensive sophisticated tools.     

High Energy Nucleus–Nucleus Collisions in View of the Multi-Peripheral Model

The hypothesis of the ulti-peripheral odel is extended to the hadron –nucleus interactions and then generalized to the nucleus –nucleus case. The processing of the odel depends on input parameters that are extracted fro the features of the experiments in this .eld.The number of encountered nucleons from both target and projectile are estimated according to the eikonal scattering approach.The screening effect due to the interaction of the projectile nucleons in successive manner with the target nucleus is considered.The rapidity distributions of fast particles are reproduced for the successive collisions in p –S and 32 S –32 S interactions at 200 A GeV.A global fair agreement is found in comparison with data of the experi ent CERN-NA-035.     

Structural,optical and electrical properties of undoped and Si-doped AlxGa1−xN thin films on Si (1 1 1) substrate grown by PA-MBE

We have studied the structural properties of undoped and Si-doped Al_xGa_1?xN/GaN/AlN on Si (1 1 1) substrate prepared by plasma-assisted molecular beam epitaxy (PA-MBE) using high-resolution X-ray diffraction (HR-XRD) and atomic force microscopy (AFM). In comparison with undoped AlGaN, the roughness and dislocation density on the surface of the AlGaN layer decrease with Si doping. Full width half maximum (FWHM) of the undoped and Si-doped samples were equal to 0.69° and 0.52°, respectively. This indicates that the Si doping improves the crystalline quality of the Al_xGa_1?xN layer compared with the undoped one. Raman scattering measurement reveals that the optical phonon modes of A₁(LO) and E₂(H) of the AlGaN show a one-mode and two-modes behavior, respectively. The Fourier-transform infrared reflectance (FTIR) investigation confirms the one-mode (two-mode) behavior of the LO (TO) phonon in our samples. This is in good agreement with Raman measurement. Finally, the barrier height (Φ_B) of undoped and Si-doped Al_xGa_1?xN samples was found to be 0.86 and 0.74 eV, respectively.     

Discrete Valuations Extend to Certain Algebras of Quantum Type

So-called “quantized” algebras are popular objects of study in non-commutative algebra. Usually such algebras are either positively graded Ore domains R with R ₀ = K a field and R = K[R ₁], R ₁ being a finite dimensional K vectorspace, or else filtered rings having a ring of forementioned type for its associated graded ring. We show that every discrete valuation of K extends to a valuation, in the sence of O. Schilling (cf. [S]), of the skewfield of fractions, Δ = Q_cl (R), of the Ore domain R (Proposition 2.3. and Corollary 2.8.). Such extension property has long been known to fail for finite dimensional skewfields over K; its validity in the case of several quantized algebras may be viewed as a consequence of the rigidity of their defining relations. Our result opens the door for a more arithmetical study of Δ e.g. in case K is a numberfield or an algebraic function field of a curve; for an application in this direction we refer to a first version of some divisor calculus started in [VW].     

Thermal,electrical and electrochemical properties of ionic liquid-doped poly(ethylene oxide)–LiTDI polymer electrolytes for Li-ion batteries

Journal of Solid State Electrochemistry - In the present study, we report the synthesis and characterisation of solid polymer electrolytes (SPEs) based on polymer poly(ethylene oxide) (PEO), salt...     

Not So Innocent After All: Interfacial Chemistry Determines Charge-Transport Efficiency in Single-Molecule Junctions

Most studies in molecular electronics focus on altering the molecular wire backbone to tune the electrical properties of the whole junction. However, it is often overlooked that the chemical structure of the groups anchoring the molecule to the metallic electrodes influences the electronic structure of the whole system and, therefore, its conductance. We synthesised electron-accepting dithienophosphole oxide derivatives and fabricated their single-molecule junctions. We found that the anchor group has a dramatic effect on charge-transport efficiency: in our case, electron-deficient 4-pyridyl contacts suppress conductance, while electron-rich 4-thioanisole termini promote efficient transport. Our calculations show that this is due to minute changes in charge distribution, probed at the electrode interface. Our findings provide a framework for efficient molecular junction design, especially valuable for compounds with strong electron withdrawing/donating backbones.     

Switching effect with memory in thallium sulfide single crystals

Thallium monosulfide single crystals have been grown and thin platelet specimens were prepared. The switching characteristics of TIS were studied in detail. Switching effect with memory was observed and reported for the first time. The influence of different variables such as temperature, light illumination, and sample thickness on the switching behaviour is considered. The obtained results are discussed.     

Spectrophotometric determination of ciprofloxacin in pure form and in tablets through charge-transfer complexation reactions

Three simple, quick and sensitive spectrophotometric methods are described for the determination of ciprofloxacin. The methods are based on the reaction of this drug as ann-electron donor with 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ), 7,7,8,8,-tetracyanoquinodimethane (TCNQ) andp-chloranil (CL) as -acceptors to give highly coloured complex species. The coloured products are quantitated spectrophotometrically at 460, 843 and 550 nm for DDQ, TCNQ and CL, respectively. Optimization of the different experimental conditions is described. Beer's law is obeyed in the concentration ranges 5–50, 1.5–15 and 20–200 g ml^–1 ciprofloxacin, but the concentration ranges for best accuracy are 10–48, 2.5–15 and 35– 195 g ml^–1 of drug for DDQ, TCNQ and CL, respectively. The relative standard deviations are less than 1.5%. Applications of the suggested methods to ciprofloxacin tablets are presented and compared with the USP method. The stability constants of the 11 DDQ and CL complexes were 1.086 × 10⁴ and 2.581 × 10⁴ lmol^–1, respectively, whereas for the 12 TCNQ complex it was 3.62 × 10⁸1. mol^–1.     

Conductance peaks in open quantum dots

We present a simple measure of the conductance fluctuations in open ballistic chaotic quantum dots, extending the number of maxima method originally proposed for the statistical analysis of compound nuclear reactions. The average number of extreme points (maxima and minima) in the dimensionless conductance T as a function of an arbitrary external parameter Z is directly related to the autocorrelation function of T(Z). The parameter Z can be associated with an applied gate voltage causing shape deformation in quantum dot, an external magnetic field, the Fermi energy, etc. The average density of maxima is found to be <ρ(Z)>=α(Z)/Z(c), where α(Z) is a universal constant and Z(c) is the conductance autocorrelation length, which is system specific. The analysis of <ρ(Z)> does not require large statistic samples, providing a quite amenable way to access information about parametric correlations, such as Z(c).