A new quaternary semiconductor compound (Ba2Sb4GeS10): Ab initio study

Abstract

The newly synthesised Ba₂Sb₄GeS₁₀ compound is notable because of the interesting features of the quaternary Sb-containing materials. The first principle method has been used to determine the physical properties of this compound. In particular, the electronic structure has been analysed using both conventional GGA-PBE and HSE06 functional. The values of the band gap for PBE and HSE06 calculations were 1.324 and 1.84 eV, respectively. The calculated elastic constants were used to predict polycrystalline mechanical properties. The estimated Vickers hardness (2.7 GPa) values show that Ba₂Sb₄GeS₁₀ is soft matter. Moreover, the vibrational properties of the compound have been studied. The calculation of the elastic constants and phonon dispersion curves indicates that the Ba₂Sb₄GeS₁₀ compound is stable both mechanically and dynamically. Furthermore, the minimum thermal conductivity and optical properties, such as dielectric functions and energy loss function, have also been discussed in detail in this paper.     

A first-principles studies on TlX (X=P, As)

We present an ab initio study of the structural, electronic and thermodynamic properties of TlX(X=P,As). The plane-wave pseudopotential approach to the density-functional theory within the LDA and GGA approximations implemented in VASP (Viena Ab-initio Simulation Package) is used. The calculated lattice parameter, elastic constants, and band structures are compared with other available theoretical results, and good agreement is obtained. In addition, we have calculated the transition pressure (P _t ) from zinc-blende (ZB) to (rock-salt) NaCl structures, and have examined some thermodynamic properties.      

Utilization of transport efficacy of novel calix[4]arene-embedded polymer inclusion membrane towards trace metals

In this study, 25,27-bis(3-mercaptopropoxyl)-26,28-dihydroxy calix[4]arene was successfully synthesized from the reaction of calix[4]arene-dialkylbromide derivative with thiourea. The structure of 25,27-bis(3-mercaptopropoxyl)-26,28-dihydroxy calix[4]arene was fully characterized using ¹HNMR, ¹³CNMR and elemental analysis techniques. The obtained mercapto-substituted calix[4]arene derivative was employed as an additive material along with cellulose triacetate (CTA) and 2-nitrophenyl octyl ether (o-NPOE) for the preparation of a novel polymer inclusion membrane (C@PIM). The structure and surface morphology of mercapto-substituted calix[4]arene-embedded polymer inclusion membrane was determined using thermogravimetric analysis, scanning electron microscopy and elemental analysis techniques. Donnan dialysis system was also used to assess the transport efficacy of C@PIM towards Pb(II), Zn(II), Cu(II), Ni(II), Cd(II) and Co(II) ions. The results show that new C@PIM exhibited 99% transport efficacy but also selectivity toward Ni(II) and other ions.     

Synthesis and catalytic properties of 1‐alkyl‐2‐imidazolineruthenium(II) complexes

New [RuCl₂(imidazoline)(arene)] complexes have been prepared. The complexes were characterized by conventional spectroscopic methods and elemental analyses. Upon reaction with 1,1‐diphenylprop‐2‐ynol they generate catalyst precursors that can perform the cycloisomerization of diallyltosylamide into N‐tosyl‐α‐methylenepyrrolidine. Copyright © 2004 John Wiley & Sons, Ltd.     

Resonant non-linear vibrations of continuous systems—II Damped and transient behavior

The method presented in Part I is extended to cover the damped and transient behavior of nonlinear systems described by equations of the form u_ss?u_yy?εf(u,u_y, u_yys,…,s) = 0. The method is presented by application to the equation u_ss?u_yy?εu_yys?εu²_yu_yy= 0. Similar to the undamped case it is again shown that the PDE requires an infinite number of periodicity conditions to correctly characterize the resonant region. However, damping eliminates some of the branches of the amplitude-frequency spectrum of the undamped case. In fact, for ε = 0.25 all but the outermost branch disappear. A method of multiple time scales is presented for the study of the transient behavior and the stability of the branches for steady vibrations. The stability analysis yields an interior stable point in the amplitude-frequency spectrum which has no analog in the Duffing equation. Finally via the multiple scale procedure in the spirit of the early work of Zabusky and Kruskal one obtains forced Burgers and Korteweg-de Vries equations on a finite interval.     

Characterization of the Impact of Classical Cell-culture Media on the Response of Electrochemical Sensors

Biocompatibility testing is usually performed through staining and imaging of cell lines. We propose here to monitor cytotoxicity through real-time measurement of metabolites specifically issued from cell stress behaviour using a multiparametric electrochemical (bio)sensing platform. However, the composition of culture media varies widely according to the requirements of the utilized cell lines. This matter may have significant effects on the sensor's sensitivity. With this mind, the sensitivity of four electrochemical (bio)sensors (pH, hydrogen peroxide, nitric oxide/nitrite (NO and its by-product) and lactate) is investigated in different cell culture media. The main culture media studied were Minimum Essential Medium Eagle (MEM), Dulbecco's Modified Eagle Medium (DMEM), Williams’ Medium E and RPMI 1640 medium that were the recommended culture media for the cell types to be monitored. This work shows the impact of the different cell culture media on the performances of the different sensors (limit of detection, sensitivity, selectivity, response time and dynamic range). More particularly, FBS strongly impacts the response of the amperometric (bio)sensors. Then, cellular viability testing was effected within optimized medium (FBS content) for electrochemical sensor read-outs in the case of short-term cultures (one day) devoted to cytotoxicity testing. Real-time electrochemical monitoring provides important additional information about cell behaviour during biocompatibility testing that might be further implemented in different settings including pharmaceutical efficacy and biomaterials applications.