Simulation of ion beam extraction and focusing system

The characteristics of ion beam extraction and focused to a volume as small as possible were investigated with the aid of computer code SIMION 3D version 7. This has been used to evaluate the extraction characteristics (accel-decel system) to generate an ion beam with low beam emittance and high brightness. The simulation process can provide a good study for optimizing the extraction and focusing system of the ion beam without any losses and transported to the required target. Also, a study of a simulation model for the extraction system of the ion source was used to describe the possible plasma boundary curvatures during the ion extraction that may be affected by the change in an extraction potential with a constant plasma density meniscus.     

Emulsion polymerization of vinyl chloride,potassium persulfate decomposition

Decomposition of potassium persulfate in sodium dodecyl sulfate solutions (of concentrations under and above CMC) and in the presence of poly(vinyl chloride) and vinyl chloride was studied. The decomposition rate has a maximum close to the CMC value of the final solutions. On the basis of experimental data a hemolytic mechanism in which a radical derived from dodecyl sulfate participates is proposed.     

Effect of the Terminal Acceptor Unit on the Performance of Non-Fullerene Indacenodithiophene Acceptors in Organic Solar Cells

Four acceptor–donor–acceptor (A–D–A)-type molecules bearing indacenodithiophene as donating central core and various end-capping acceptor units have been designed and synthesised as n-type materials suitable for organic solar cells (OSCs). The studied optical and electrochemical properties supported by theoretical calculations revealed that the nature and the strength of the terminal groups exert a decisive influence on the polymer bulk-heterojunction OSC performance.     

Fluorescence and Time-Resolved Delayed Luminescence of Porphyrins in Organic Solvents and Polymer Matrices

Porphyrin dyes fulfill an essential function in photosynthesis and are important in photodynamic therapy and in a range of electronic devices. Their spectroscopic characteristics may play a crucial role in these processes. The spectral properties of two porphyrin dyes: tetraphenylporphyrin and tetraphenysulfporphyrin in organic solvents (acetone, chloroform, methyl alcohol, and dimethyl-sulfoxide) and in polyvinyl alcohol and poly(methylmethacrylate) films have been investigated. Absorption, fluorescence, and microsecond time-resolved delayed luminescence spectra have been measured at room temperature. The existence of different aggregated dye forms in the ground and excited states has been demonstrated. The manifold of dye species depends on the solvent/polymer. In the case of the polymers, it also depends on the solvent used to coat the polymer film. Delayed luminescence spectra and decay times of the two porphyrins in the different solutions and in polymeric matrices suggest that different mechanisms of deexcitation of the singlet excited states may be responsible for their generation in these and other porphyrin dyes.     

Synthesis of novel pentafluorosulfanylfurans. Two retro-Diels-Alder approaches

The first examples of furan substituted with an SF5 group are reported. 3-pentafluorosulfanylfurans were prepared from their respective 2-pentafluorosulfanyl-5-cyano-7-oxabicyclo[2.2.1]hept-2-ene precursors via retro-Diels-Alder reactions. Also, a tandem cycloaddition/retrocycloaddition reaction between 4-phenyloxazole and 1-pentafluorosulfanylhex-1-yne was used to prepare 3-pentafluorosulfanyl-4-butylfuran. [reaction: see text].     

Smart poly(2-hydroxyethyl methacrylate/itaconic acid) hydrogels for biomedical application

pH- and temperature-sensitive hydrogels, based on 2-hydroxyethyl methacrylate (HEMA) and itaconic acid (IA) copolymers, were prepared by γ-irradiation and characterized in order to examine their potential use in biomedical applications. The influence of comonomer ratio in these smart copolymers on their morphology, mechanical and thermal properties, biocompatibility and microbe penetration capability was investigated. The mechanical properties of copolymers were investigated using the dynamic mechanical analysis (DMA), while their thermal properties and morphology were examined by thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The morphology, mechanical and thermal properties of these hydrogels were found to be suitable for most requirements of biomedical applications. The in vitro study of P(HEMA/IA) biocompatibility showed no evidence of cell toxicity nor any considerable hemolytic activity. Furthermore, the microbe penetration test showed that neither Staphylococcus aureus nor Escherichia coli passed through the hydogel dressing; thus the P(HEMA/IA) dressing could be considered a good barrier against microbes. All results indicate that stimuli-responsive P(HEMA/IA) hydrogels have great potential for biomedical applications, especially for skin treatment and wound dressings.     

Physical,Thermal and Biological Properties of Yellow Dyes with Two Azodiphenylether Groups of Anthracene

Two yellow bis-azo dyes containing anthracene and two azodiphenylether groups (BPA and BTA) were prepared, and an extensive investigation of their physical, thermal and biological properties was carried out. The chemical structure was confirmed by the FTIR spectra, while from the UV–Vis spectra, the quantum efficiency of the laser fluorescence at the 476.5 nm was determined to be 0.33 (BPA) and 0.50 (BTA). The possible transitions between the energy levels of the electrons of the chemical elements were established, identifying the energies and the electronic configurations of the levels of transition. Both crystals are anisotropic, the optical phenomenon of double refraction of polarized light (birefringence) taking place. Images of maximum illumination and extinction were recorded when the crystals of the bis-azo compounds rotated by 90° each, which confirms their birefringence. A morphologic study of the thin films deposited onto glass surfaces was performed, proving the good adhesion of both dyes. By thermal analysis and calorimetry, the melting temperatures were determined (~224–225 °C for both of them), as well as their decomposition pathways and thermal effects (enthalpy variations during undergoing processes); thus, good thermal stability was exhibited. The interaction of the two compounds with collagen in the suede was studied, as well as their antioxidant activity, advocating for good chemical stability and potential to be safely used as coloring agents in the food industry.     

Tartrazine: physical,thermal and biophysical properties of the most widely employed synthetic yellow food-colouring azo dye

Journal of Thermal Analysis and Calorimetry - The food-colouring dye tartrazine is a significant additive and in the same time a biologically active material. Thermal behaviour of trisodium...