Microporous La–Metal–Organic Framework (MOF) with Large Surface Area

A microporous La–metal‐organic framework (MOF) has been synthesized by the reaction of La(NO₃)₃ ? 6 H₂O with a ligand 4,4′,4′′‐s‐triazine‐1,3,5‐triyltri‐p‐aminobenzoate (TATAB) featuring three carboxylate groups. Crystal structure analysis confirms the formation of 3D MOF with hexagonal micropores, a Brunauer–Emmett—Teller (BET) surface area of 1074 m² g^?1 and high thermal and chemical stability. The CO₂ adsorption capacities are 76.8 cm³ g^?1 at 273 K and 34.6 cm³ g^?1 at 293 K, a highest measured CO₂ uptake for a Ln–MOFs.     

Electrical and optical properties of silver doped indium oxide thin films prepared by reactive DC magnetron sputtering

Silver doped indium oxide (In_2−x Ag_x O_3−y) thin films have been prepared on glass and silicon substrates at room temperature (300 K) by reactive DC magnetron sputtering technique using an alloy target of pure indium and silver (80: 20 atomic %. The magnetron power (and hence the metal atom sputter flux) is varied in the range 40-80 W. The energy dispersive analysis of X-ray (EDAX) results show that the silver content in the film decreases with increasing magnetron power. The grain size of these films is of the order of 100 nm. The resistivity of these films is in the range 10⁻²-10⁻³ Ω cm. The work function of the silver-indium oxide films (by Kelvin Probe) are in the range: 4.64-4.55 eV. The refractive index of these films (at 632.8 nm) varies in the range: 1.141-1.195. The optical band gap of indium oxide (3.75 eV) shrinks with silver doping. Calculations of the partial ionic charge (by Sanderson's theory) show that silver doping in indium oxide thin films enhance the ionicity.     

无限横观各向同性弹性圆柱中刚性圆盘的扭转振动

分析了无限横观各向同性弹性圆柱中，刚性圆盘的扭转振动问题．绘制的图形显示了材料的各向异性性质对应力强度因子的影响．     

Synthesis and Structure of Unprecedented Samarium Complex with Bulky Bis‐iminopyrrolyl Ligand via Intramolecular C=N Bond Activation

An unprecedentate samarium complex of the molecular composition [{κ³‐{(Ph₂CH)N=CH}₂C₄H₂N)}{κ³‐{(Ph₂CHN=CH)(Ph₂CHNCH)C₄H₂N}Sm}₂] ( 2 ), which was isolated by the reaction of a potassium salt of 2,5‐bis{N‐(diphenylmethyl)‐iminomethyl}pyrrolyl ligand [K(THF)₂{(Ph₂CH)N=CH}₂C₄H₂N)] ( 1 ) with anhydrous samarium diiodide in THF at 60 °C through the in situ reduction of imine bond is presented. The homoleptic samarium complex [[κ³‐{(Ph₂CH)–N=CH}₂C₄H₂N)]₃Sm] ( 3 ) can also be obtained from the reaction of compound 1 with anhydrous samarium triiodide (SmI₃) in THF at 60 °C. The molecular structures of complexes 2 and 3 were established by single‐crystal X‐ray diffraction analysis. The molecular structure of complex 2 reveals the formation of a C–C bond in the 2,5‐bis{N‐(diphenylmethyl)iminomethyl}pyrrole ligand moiety (Ph₂Py^–). However, complex 3 is a homoleptic samarium complex of three bis‐iminopyrrolyl ligands. In complex 2 , the samarium ion adopts an octahedral arrangement, whereas in complex 3 , a distorted three face‐centered trigonal prismatic mode of nine coordination is observed around the metal ion.     

Analysis for optimal pattern synthesis of time modulated concentric circular antenna array using memetic firefly algorithm

In this paper the optimal performance of time modulated nine-ring concentric circular antenna array with isotropic elements has been studied based on an evolutionary optimization algorithm hybridized with local heuristic search called memetic firefly algorithm (MFA). The firefly algorithm has been applied followed by Nelder–Mead simplex method for the local heuristic search to achieve the optimal fine tuning. Other algorithms like real coded genetic algorithm (RGA) and particle swarm optimization (PSO) have been used for the comparison purpose. The comparisons among the algorithms have been made with two case studies as Case-1 and Case-2, and with two different fitness functions \((f_{{ fitness}1}, f_{{ fitness}2})\) and three control parameters like inter-element uniform/non-uniform spacing in rings, inter-ring radii and the switching-on times of rings. The simulation results show that the MFA outperforms RGA and PSO for both the cases Case-1, Case-2 and \(f_{{ fitness}1}\), \(f_{{ fitness}2}\), respectively with respect to better side lobe level (SLL). The fitness function \(f_{{ fitness}2}\) is better than the \(f_{{ fitness}1}\) with respect to sideband level. Apart from this, powers radiated at the centre/fundamental frequency and the first two sideband frequencies, and dynamic efficiency have been computed. It is found that power radiated by any sideband frequency is much less as compared to the power radiated at the centre frequency. It has been observed that as the sideband frequency increases, SBL decreases to the greater extent as compared to SLL. As per authors’ knowledge there is a little research contribution by any other previous researcher regarding numerical computation of radiation characteristics as SBLs, powers radiated at the fundamental frequency and its two sideband frequencies, directivity, and dynamic efficiency for time-modulated CCAA.     

Synthesis and structural characterization of copper(II) and vanadium(V) complexes of pyridyl/pyrimidyl–pyrazole derived Schiff base ligands – Metal specific adjustment of ligand binding mode

Two mononuclear copper(II) complexes [Cu(L₁)ClO₄] (1), [Cu(L₂)ClO₄] (3) and two mononuclear vanadium(V) complexes [{VO(L₁)(OCH₃)(CH₃OH)}{VO(L₁)(OCH₃)}] (2) and [VO(L₂) (OCH₃)(CH₃OH)] (4) have been synthesized using two Schiff base ligands HL₁ [N′-(2-hydroxybenzylidene)-5-methyl-1-(pyridin-2-yl)-1H-pyrazole-3-carbohydrazide] and HL₂ [1-(4,6-dimethylpyrimidin-2-yl)-N′-(2-hydroxybenzylidene)-5-methyl-1H-pyrazole-3-carbohydrazide]. These two similar ligands HL₁ and HL₂ in their ‘ketoimine’ form function as mononegative NNNO tetradentate ones towards the Cu(II) centre forming square planar part of the square pyramidal geometry. Where as the same ligands in their ‘imineol’ form behave as binegative ONO tridentate ones to form their V(V) analogues. In the asymmetric unit of 2, there are two independent V(V) complex molecules differing in their conformations as well as in coordination environment – octahedral V(V) in ‘unit A’ is hexa-coordinated while that in ‘unit B’ being penta-coordinated is square pyramidal. Vanadium atom in 4 is in octahedral geometry with NO₅ chromophore. The ligands HL₁ and HL₂ have been synthesized for the first time in our laboratory and characterized by X-ray crystallography and spectroscopy. The complexes (1, 2 and 4) are also characterized by X-ray crystallography, spectroscopic and electrochemical studies.     

Challenges and prospects of metal sulfide materials for supercapacitors

Worldwide, the research on advanced materials for energy storage devices has drawn greater attention. Numerous works on different energy storage materials has been reported and still continuing. Among the energy storage devices, electrochemical supercapacitors (ESs) are one of the most investigated topics. The globalization and increasing demand of smart and flexible devices has forced the current research to develop low-cost, high-energy density and stable ESs. In this regard, metal sulfides (MSs)–based materials have been envisioned for ESs applications owing to their unique and promising properties. Recently, several research articles have been published on MSs-based electrodes for ESs with enhanced performances. This review presents a brief survey on such recent developments towards synthesis of MSs and their use as an efficient electrode material in ESs. The challenges and future aspect involved with MSs to develop and establish it as a promising energy storage material are also discussed.     

Octet baryons in the independent-quark-model approach based on the dirac equation with a power-law potential

Several properties of octet baryons such as (i) the magnetic moment, (ii) (G_A/G_v)_n for neutron β-decay and (iii) the charge radius of the proton have been calculated in a simple independent-quark model under the assumption that the individual constituent quarks are confined, in first approximation, by a relativistic power-law potential V_q(r)=(1+β)(a^v+1r^v+V₀) with a, v>0. In view of the simplicity of the model, the results obtained are quite encouraging.     

A non-coulombic effective power-law potential for the heavy quarkoniums

An effective power-law potential of the form V(r) = 6.08 r^0.106?6.41 is found to describe satisfactorily the gross features of the mass spectra and the leptonic width ratios of the c$\text{c}$ and b$\text{b}$ systems in a flavour-independent manner.