Theoretical Investigation of Tunable Goos-Hänchen Shifts in a Four-Level Quantum System

Goos-Hänchen (GH) shifts in the reflected and transmitted light have been discussed in a cavity with four-level quantum system. It is realized that the refraction index of intracavity medium can be negative by manipulating the external coherent laser fields. For the negative refraction index of intracavity medium, the GH shifts of reflected and transmitted light beams have been analyzed in a parametric condition. It is found that due to modulation of laser signals and relative phase between applied fields, large and tunable GH shifts in reflected and transmitted light beams can be obtained.     

Synthesis and Study of 1-Alkenyl-2-propargyloxy-3-aminomethylbenzenes as Acid Corrosion Inhibitors and Antimicrobial Additives to Cutting Fluids

Russian Journal of Applied Chemistry - A series of polyfunctional organic compounds, 1-propenyl- and 1-allyl-2-propargyloxy-3-aminomethylbenzenes containing simultaneously an aminomethyl group and...     

A comparative study of sequentially layer-deposited and co-deposited Co–Mn oxides as potential redox capacitors

Layers of cobalt and manganese oxides were co-deposited or deposited on top of each other or next to each other by potentiostatic method onto stainless steel substrate. Deposition potentials of 1 and −1 V for the anodic and cathodic depositions were employed. Specific capacitance values in the range of 38.5–78 F g⁻¹ were found with cobalt oxide on top of manganese oxide having the lowest and manganese oxide on top of cobalt oxide having the highest capacitances. The usefulness of the electrodes was characterized by cyclic voltammetry, charge–discharge cycling, and electrochemical impedance spectroscopy in 2 M NaOH electrolyte for redox supercapacitor applications. The latter presented the best charge/discharge behavior with no voltage drop due to lower ohmic resistance in prepared substrate; although the steadiest current observed in the course of voltammetry was due to the former. The evaluated double layer and specific capacitances for co-deposited sample according to the impedance studies were 1.75 and 47.5 F g⁻¹, respectively, being in good agreement with voltammetric measurements.     

Synthesis of α‐Aminonitriles and 5‐Substituted 1H‐Tetrazoles Using an Efficient Nanocatalyst of Fe3O4@SiO2–APTES‐supported Trifluoroacetic Acid

Fe₃O₄@SiO₂–APTES‐supported trifluoroacetic acid nanocatalyst was used for the one‐pot synthesis of α‐aminonitriles via a three‐component reaction of aldehydes (or ketones), amines, and sodium cyanide. This method produced a high yield of 75–96% using only a small amount of the catalyst (0.05 g) in EtOH at room temperature. The catalyst was also employed for the synthesis of 5‐substituted 1H‐tetrazoles from nitriles and sodium azide in EtOH at 80°C. The tetrazoles were produced with good‐to‐excellent yields in a short reaction time of 4 h. Both synthetic methods were carried out in the absence of an organic volatile solvent. Because the supported trifluoroacetic acid generated a solid acid on the surface, thus the acid corrosiveness was not a serious challenge. This heterogeneous nanocatalyst was magnetically recovered and reused several times without significant loss of catalytic activity.     

Basic ionic liquid anchored on UiO-66-NH2 metal–organic framework: a stable and efficient heterogeneous catalyst for synthesis of xanthenes

Research on Chemical Intermediates - In this study, the Zr-based metal–organic framework, UiO-66-NH2, was modified with ionic liquid (dibutylimidazolium bromide) to generate a platform for...     

Supramolecular synthesis of 3,4-dihydropyrimidine-2(1H)-one/thiones under neat conditions

An efficient solvent free method for the synthesis of various 3,4-dihydropyrimidin-2(1H)-one/thiones in excellent yields using sulfonatedβ-cyclodextrine as recyclable catalyst is described.Sulfonatedβ-cyclodextrine was found to be efficient,recyclable heterogeneous catalyst and showed rate enhancements,high yields and short reaction times in this transformation.     

Nonlinear absorption and refraction effect on thermal lensing of solid-state laserrods

In this work, the effect of nonlinear absorption and refraction on thermal lensing of an end-pumped solid-state laser rod is investigated. At high input pump powers and on the focused region of thermal lensing, nonlinear responses of the active medium will be important. By considering the nonlinear absorption and refraction, the intensity distribution inside the rod is obtained. A convergence lens models the intensity dependency of the refractive index. By modeling of the laser rod with some contributed effective lenses, the stability condition of a typical laser resonator is investigated.     

Controlling the optical bistability in a Λ-type atomic system via incoherent pump field

We investigated optical bistability (OB) and the absorption properties of a weak probe field in a three-level Λ-type atomic system confined in a unidirectional ring cavity via incoherent pump field. We found that the threshold of OB and the probe field absorption can be controlled by the rate of incoherent pump field. No laser field was used in the pumping processes.