Synthesis and Reactions of Some New Pyrrolylfuro[2,3‐d]Pyrimidines and Pyrrolopyrazinofuropyrimidines

5‐Amino‐4‐methyl‐2‐phenyl‐6‐substitutedfuro[2,3‐d]pyrimidines ( 2a‐c ) were reacted with 2,5‐dimethoxytetrahydrfuran to afford the pyrrolyl derivatives 3a‐c . Compound 3a was chosen as intermediate for the synthesis of poly fused heterocycles incorporated furopyrimidines moiety 4–11 . Some of the synthesized compounds were screened for their antibacterial and antifungal activities.     

On the Discrete Hardy Inequality

Necessary and sufficient conditions for the boundedness of thediscrete Hardy operator of the form , from to when 0 < q < 1 <p , is given.     

An efficient synthesis and cytotoxic activity of 2‐(4‐chlorophenyl)‐1H–benzo[d]imidazole obtained using a magnetically recyclable Fe3O4 nanocatalyst‐mediated white tea extract

A simple and efficient procedure has been developed for the synthesis of biologically relevant 2‐substituted benzimidazoles through a one‐pot condensation of o‐phenylenediamines with aryl aldehydes catalysed by iron oxide magnetic nanoparticles (Fe₃O₄ MNPs) in short reaction times with excellent yields. In the present study, Fe₃O₄ MNPs synthesized in a green manner using aqueous extract of white tea (Camelia sinensis) (Wt‐Fe₃O₄ MNPs) were applied as a magnetically separable heterogeneous nanocatalyst to synthesize 2‐(4‐chlorophenyl)‐1H–benzo[d]imidazole which has potential application in pharmacology and biological systems. Fourier transform infrared and NMR spectroscopies were used to characterize the 2‐(4‐chlorophenyl)‐1H–benzo[d]imidazole. In vitro cytotoxicity studies on MOLT‐4 cells showed a dose‐dependent toxicity with non‐toxic effect of 2‐(4‐chlorophenyl)‐1H–benzo[d]imidazole, up to a concentration of 0.147 µM. The green synthesized Wt‐Fe₃O₄ MNPs as recyclable nanocatalyst could be used for further research on the synthesis of therapeutic materials, particularly in nanomedicine, to assist in the treatment of cancer.     

Structural,optical and electrical properties of undoped and Si-doped AlxGa1−xN thin films on Si (1 1 1) substrate grown by PA-MBE

We have studied the structural properties of undoped and Si-doped Al_xGa_1?xN/GaN/AlN on Si (1 1 1) substrate prepared by plasma-assisted molecular beam epitaxy (PA-MBE) using high-resolution X-ray diffraction (HR-XRD) and atomic force microscopy (AFM). In comparison with undoped AlGaN, the roughness and dislocation density on the surface of the AlGaN layer decrease with Si doping. Full width half maximum (FWHM) of the undoped and Si-doped samples were equal to 0.69° and 0.52°, respectively. This indicates that the Si doping improves the crystalline quality of the Al_xGa_1?xN layer compared with the undoped one. Raman scattering measurement reveals that the optical phonon modes of A₁(LO) and E₂(H) of the AlGaN show a one-mode and two-modes behavior, respectively. The Fourier-transform infrared reflectance (FTIR) investigation confirms the one-mode (two-mode) behavior of the LO (TO) phonon in our samples. This is in good agreement with Raman measurement. Finally, the barrier height (Φ_B) of undoped and Si-doped Al_xGa_1?xN samples was found to be 0.86 and 0.74 eV, respectively.     

Two criteria to check whether ideals are direct sums of cyclically presented modules

A famous theorem of commutative algebra due to I. M. Isaacs states that “if every prime ideal of R is principal, then every ideal of R is principal”. Therefore, a natural question of this sort is “whether the same is true if one weakens this condition and studies rings in which ideals are direct sums of cyclically presented modules?” The goal of this paper is to answer this question in the case R is a commutative local ring. We obtain an analogue of Isaacs's theorem. In fact, we give two criteria to check whether every ideal of a commutative local ring R is a direct sum of cyclically presented modules, it suffices to test only the prime ideals or structure of the maximal ideal of R. As a consequence, we obtain: if R is a commutative local ring such that every prime ideal of R is a direct sum of cyclically presented R-modules, then R is a Noetherian ring. Finally, we describe the ideal structure of commutative local rings in which every ideal of R is a direct sum of cyclically presented R-modules.     

Studies on photoinduced effects in pulse-electrodeposited Ag/Hg-1212/CdSe hetero-nanostructures

Metal/superconductor/semiconductor (Ag/Hg-1212/CdSe) hetero-nanostructures have been fabricated using pulse-electrodeposition technique and are characterized by X-ray diffraction (XRD), full-width at half-maximum (FWHM) and scanning electron microscopy (SEM) studies. The junction capacitance of Ag/Hg-1212, Hg-1212/CdSe and Ag/Hg-1212/CdSe heterojunctions is measured in dark and under laser irradiation at room temperature. The nature of the junction formed and built-in-junction potentials were determined. The increase in carrier concentration across the junction due to photo-irradiation has been observed.     

Effect of laser irradiation of C-V characteristics of electrodeposited Ag/Tl-2223/CdSe hetero-nanostructures

One of the innovative technological directions for the high-temperature superconductors has been persued by fabricating the heteroepitaxial multilayer structures such as superconductor-semiconductor heterostructures. In the present investigation, metal/superconductor/semiconductor (Ag/Tl-2223/CdSe) hetero-nanostructures have successfully been fabricated using dc electrodeposition technique and were characterized by X-ray diffraction (XRD), full-width at half-maximum (FWHM) and scanning electron microscopy (SEM) studies. The measurement of junction capacitance as a function of biasing voltage was used for the estimation of junction built-in-potential (V _D) and to study the charge distribution in a heterojunction. The Mott-Schottky plots were measured for each junction in dark and under the photo-irradiation. The effect of laser irradiation on C-V characteristics of hetero-nanostructure has been studied.     

在不同温度下球墨鑄铁的冲击性能

本文描述高温冲击实验的技术,以及由-85℃至1070℃的铸态和锻造后的球墨铸铁的冲击性能。研究结果找到了基体主要为铁素体的球墨铸铁的两个变脆温度范围(-20℃以下和550℃至700℃之间)和一个比较具有韧性的温度范围(850℃与1050℃之间)。在这些温度范围内,曾考查试样的断口情况和断裂时的弯曲角度,并与其基体组织的变化相联系,进行讨论。最后,本文指出研究结果在球墨铸铁的应用上所起的作用,以及在球墨铸铁热加工时对于选择热加工温度的意义。