An effective BINAP and microwave accelerated palladium-catalyzed amination of 1-chloroisoquinolines in the synthesis of new 1,3-disubstituted isoquinolines

A facile and microwave accelerated reaction of 1-chloro-3-(4-chlorophenyl)isoquinoline with various heterocyclic amines, catalyzed by Pd, in the presence of BINAP additive and sodium carbonate as the base, leads to the formation of 3-(4-chlorophenyl)-1-(1H-1,2,3-triazol-1-yl)isoquinoline, 3-(4-chlorophenyl)-1-(1H-imidazol-1-yl)isoquinoline and 3-(4-chlorophenyl)-1-(1H-1,2,4-triazol-1-yl)isoquinoline via Buchwald protocol in good yields. Similarly pyrazolylisoquinolines are also reported.     

A Novel Gain-Clamped Erbium Doped Fiber Amplifier for Wavelength Division Multiplexed Systems

Amplification of multiwavelength signals by an erbium-doped fiber amplifier (EDFA) is becoming critical, due to the proliferation of wavelength division multiplexed systems. However, when a standard EDFA is employed, the dissimilarities among the signals’ gain may prove unacceptable. Thus, a novel gain-clamped EDFA is proposed here to tackle the issue of gain tilt. The suitability of the configuration is then investigated through a numerical model, which is developed based on the standard EDFA and fiber laser models.     

Generation of sub wavelength multiple focal hole segments using azimuthally polarized annular multi-Gaussian beam

We propose a new approach for generating multiple focal hole segment of sub wavelength size, by tight focusing of phase modulated annular multi-Gaussian beam. The focusing properties are investigated theoretically by vector diffraction theory. We observed that focal segment with multiple focal rings structure separated with different axial distance can be generated by properly tuning the phase of the incident azimuthally polarized annular multi-Gaussian beam. Potential applications of this focal shaping technique are also discussed.     

Simple and Convenient Methods for the Synthesis of Indolo[3,2-c]acridines

The reaction of 2,3,4,9-tetrahydro-1H-carbazol-1-ones with anthranilic acid in POCl₃ yielded 7-chloro-5,6-dihydro-13H-indolo[3,2-c]acridines, while the same on reaction with isatin under the Pfitzinger reaction condition yielded 5,6-dihydro-13H-indolo[3,2-c]acridine-7-carboxylic acids. The latter reaction was carried out in different basic condition, because of, NaOH yielded more yield instead of KOH. Both the obtained products were treated with Pd/C in diphenyl ether to yield 13H-Indolo[3,2-c]acridines.     

Silicon-based thiourea-mediated and microwave-assisted thio-Michael addition under solvent-free reaction conditions

Silicon-based thiourea (SiliaBond® Thiourea) (Si-THU), a heterogeneous catalyst, has been applied to the highly selective C-S bond formation via Michael addition of thiols to α,β-unsaturated carbonyl compounds under solvent-free conditions at 55–60°C. The thio-Michael addition products were obtained in an excellent yield under optimised conditions. This methodology involving a metal-free as well as a metal scavenger catalyst has been found to be an alternative method for the thio-Michael addition reaction.     

Focus shaping of tightly focused TEM11 mode cylindrically polarized Laguerre Gaussian beam by diffractive optical element

We study the focus shaping of tightly focused TEM₁₁ mode cylindrically polarized Laguerre Gaussian beam with high numerical aperture lens axicon system is investigated theoretically by vector diffraction theory. The intensity pattern at the focus can be tailored by appropriately adjusting the rotation angle. We show that the high NA lens axicon system can generates a sub wavelength focal spot, focal hole, focal splitting and flat-topped focal shapes with extended depth of focus.     

Focal shift of radially polarized axisymmetric Bessel modulated Gaussian beam with radial variance phase plate

Focal shift of the radially polarized axisymmetric QBG beam with radial variance phase plate is investigated theoretically by vector diffraction theory. Axisymmetric Bessel modulated Gaussian beam with quadratic radial dependence (QBG beam) has attracted much attention recently. Calculation results show that focus shifts considerably by changing the phase parameter C that indicates the radial phase variance speed. Under condition of beam parameter μ of radially polarized axisymmetric QBG beam, there is one focal spot that shifts far away from optical aperture on increasing C. When increases the value of beam parameter, there may occur two focal peaks that also shift remarkably on increasing C.     

Recent studies on small molecular and polymeric hole-transporting materials for high-performance perovskite solar cells

A decade of significant research has led to the emergence of photovoltaic solar cells based on perovskites that have achieved an exceptionally high-power conversion efficiency of 26.08%. A key breakthrough in perovskite solar cells (PSCs) occurred when solid hole-transporting materials (HTMs) replaced liquid electrolytes in dye-sensitized solar cells (DSSCs), because HTMs play a crucial role in improving photovoltaic performance as well as cell stability. This review is mainly focused on the HTMs that are responsible for hole transport and extraction in PSCs, which is one of the crucial components for efficient devices. Here, we have reviewed small molecular as well as polymeric HTMs that have been reported in the last two years and discussed their performance based on the analysis of their molecular architectures. Finally, we include a perspective on the molecular engineering of new functional HTMs for highly efficient stable PSCs.     

A novel exergy based charge optimisation for a mobile air conditioning system

Journal of Thermal Analysis and Calorimetry - In this paper, a novel exergy based charge optimisation technique is proposed instead of coefficient of performance (COP) based...