Quasi Right Factorization Structures as Presheaves

In this article the notion of quasi right factorization structure in a category X\cal{X} is given. The main result is a one to one correspondence between certain classes of quasi right factorization structures and 2-reflective subobjects of a predefined object in Lax(PrOrd^Xop) \bf{\it{L}}\it{ax}({\it{PrOrd}}^{\bf{\cal{X}}^{op}}). Also a characterization of quasi right factorization structures in terms of images is given. As an application, the closure operators are discussed and it is shown that quasi closed members of certain collections are quasi right factorization structures. Finally several examples are furnished.     

Comparison of Multi‐walled Carbon Nanotubes and Poly(3‐octylthiophene) as Ion‐to‐Electron Transducers in All‐Solid‐State Potassium Ion‐Selective Electrodes

Multi‐walled carbon nanotubes (MWCNTs) were compared with poly(3‐octylthiophene) (POT) as ion‐to‐electron transducer in all‐solid‐state potassium ion‐selective electrodes with valinomycin‐based ion‐selective membranes. MWCNTs and POT were mixed with the other components of the potassium ion‐selective membrane cocktail (valinomycin, KTpClPB, o‐NPOE, PVC, THF) which was then applied on a glassy carbon (GC) substrate to prepare single‐piece ion‐selective electrodes (SPISEs). Results from potentiometric and impedance measurements showed that the MWCNT‐based electrodes have a more reproducuible standard potential and a lower overall impedance than the electrodes based on POT. Both types of electrodes showed similar sensitivity to potassium ions and no redox sensitivity.     

On finite groups with few non-normal subgroups

In this paper we characterize the finite groups having exactly two conjugacy classes of non-normal subgroups.     

Vibrational analysis of carbon nanotubes using molecular mechanics and artificial neural network

This paper presents the molecular mechanics based finite element modeling of carbon nanotubes (CNTs) and their applications as mass sensors. The beam element with elastic behavior is considered as the bond between the carbon atoms and its properties are obtained using equating continuum and molecular characteristics. The first five natural frequencies of CNTs in cantilever and doubly clamped boundary conditions (BCs) and their corresponding mode shapes are studied in detail. Furthermore, a multilayer perceptron neural network is used to predict the fundamental vibration frequencies of the CNTs with different diameters and lengths. In addition, variations of the natural frequencies of the CNTs with distorted cross sections are investigated. Moreover, the effects of some attached masses with various values on the first three natural frequencies of a considered CNT are studied here.     

Investigation on Structural,Electronic, and Thermoelectric Properties of Half-Heusler Compounds TiXSb (X = Si,Ge) under Pressure Based on Density Functional Theory (DFT)

Physics of the Solid State - Based on density functional theory, structural, electronic, and thermoelectric properties of TiXSb (X = Si, Ge) at pressures of 0, 5, 10, and 15 GPa have been...     

Optical conductivity of carbon nanotubes

The effect of electron–phonon interaction on the optical conductivity of semiconducting carbon nanotubes is studied. In this manner, the Kubo–Greenwood formula, Green's function technique and the Holstein Hamiltonian model are used. The optical conductivity of the system shows different behaviors between low and high frequency region. In the low frequency, the optical conductivity increases with electron–phonon coupling strength increasing while it has no noticeable change in the high frequency region. The results also show that the optical conductivity increases with increasing of nanotube's diameter.     

A novel and reusable magnetic nanocatalyst developed based on graphene oxide incorporated strontium nanoparticles for the facial synthesis of β‐enamino ketones under solvent‐free conditions

A novel magnetic SrFeGO nanocatalyst (NC) was synthesized through a simple sol–gel technique by introducing strontium and iron oxide nanoparticles onto graphene. The synthesized NC was characterized using FT‐IR and FE‐SEM. Subsequently, the catalytic activity of SrFeGO was tested in a reaction between β‐dicarbonyl compounds and aniline derivatives to gain β‐enamino ketone derivatives under solvent‐free conditions. It was found that SrFeGO NC is a potential catalyst for the synthesis of β‐enamino ketones. The β‐enamino ketone produced by such reactions could be isolated in high purity without the need for chromatographic purifications. The newly prepared magnetic graphene oxide nanocomposite could be recovered and reused for numerous times with no significant decrease in efficiency. Moreover, the protocol has the advantages of excellent yielding (up to 98%) in short a reaction time, benefitting an easy workup procedure and being environmentally friendly.     

Facile,capable, atom-economical one-pot multicomponent strategy for the direct regioselective synthesis of novel isoxazolo[5,4-d]pyrimidines

Research on Chemical Intermediates - Facile and efficient NaOH-promoted one-pot regioselective synthesis of 5,7-dimethyl-3-(arylamino)isoxazolo[5,4-d]pyrimidine-4,6(5H,7H)-diones and...     

The effect of synthesis procedure on the catalytic performance of isostructural ZIF‐8

We demonstrate the synthesis of isostructural zeolitic imidazole framework (ZIF‐8) using four distinct synthetic methods. Subsequently, the variations in physicochemical properties were analyzed through the catalytic reaction of CO₂ cycloaddition of epoxide. It was thus demonstrated that simply by changing the type of synthetic method for the preparation of ZIF‐8, the physicochemical properties were changed significantly which in turn influenced the catalytic activity of ZIF‐8. It was found that the synthetic method affected the crystal growth and consequently influenced the physicochemical properties which are crucial aspects in metal–organic framework applications. There is an almost exponential relationship between the reactivity of various ZIF‐8 samples in CO₂ cycloaddition of epoxide and the surface area, CO₂ adsorption and pore volume.