CuI/Fe3O4 NPs@Biimidazole IL‐KCC‐1 as a leach proof nanocatalyst for the synthesis of imidazo[1,2‐a]pyridines in aqueous medium

In the present work, an innovative leach proof nanocatalyst based on dendritic fibrous nanosilica (DFNS) modified with ionic liquid loaded Fe₃O₄ NPs and CuI salts was designed and applied for the rapid synthesis of imidazo[1,2‐a]pyridines from the reaction of phenyl acetylene, 2‐aminopyridine, and aldehydes in aqueous medium. The structure of the synthesized nanocatalyst was studied by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), Fourier transform infrared (FT‐IR), flame atomic absorption spectroscopy (FAAS), energy‐dispersive X‐ray (EDX), and X‐ray diffraction (XRD), vapor–liquid–solid (VLS), and adsorption/desorption analysis (Brunauer–Emmett–Teller [BET] equation) instrumental techniques. CuI/Fe₃O₄NPs@IL‐KCC‐1 with high surface area (225 m² g^?1) and porous structure not only exhibited excellent catalytic activity in aqueous media but also, with its good stability, simply recovered by an external magnet and recycled for eight cycles without significant loss in its intrinsic activity. Higher catalytic activity of CuI/Fe₃O₄NPs@IL‐KCC‐1 is due to exceptional dendritic fibrous structure of KCC‐1 and the ionic liquid groups that perform as strong anchors to the loaded magnetic nanoparticles (MNPs) and avoid leaching them from the pore of the nanocatalyst. Green reaction media, shorter reaction times, higher yields (71–97%), easy workup, and no need to use the chromatographic column are the advantages of the reported synthetic method.     

Modulating opto-electronic and magnetic responses of Mo- and Zn-adsorbed LiNbO3 (1 1 1) surface for advanced energy harvesting applications: A comprehensive study

This study aimed to comprehensively investigate the optoelectronic and magnetic properties of Mo, Zn/LiNbO₃ (1 1 1) material. The primary objectives were to understand the potential for manipulating the material's magnetism and to elucidate the origin of spin-polarized states and magnetic moments, particularly with respect to the unpaired d orbitals of Nb, Mo, and Zn atoms. To achieve these objectives, we employed the Pardew–Burke–Ernzerhof (PBE) method within the Generalized Gradient Approximation (GGA + U) framework. This computational approach allowed us to examine the optoelectronic and magnetic characteristics of the material in detail. Our research yielded several key findings that enhance our understanding of Mo, Zn/LiNbO₃ (1 1 1) material. We observed a modest improvement in the material's absorption capacity within the visible spectrum, accompanied by a discernible red-shift. Notably, our study involved the calculation of the dielectric function and refractive constant of the material, revealing a strong correlation between absorption trends and the dielectric constant. Furthermore, our investigation uncovered that Mo, Zn/LiNbO₃ (1 1 1) exhibits distinct conduction and valence bands, with p and d orbitals predominantly contributing to each, respectively. The energy gap of the material falls within a range of 0.30–1.04 eV. A particularly significant finding was the narrower band gap of Mo, Zn/LiNbO₃ (1 1 1) material, which can be attributed to the superposition of Mo-d and Zn-p orbit energy levels with O-p orbit energy levels, ultimately forming a covalent bond. Importantly, our research demonstrated the material's heightened optical absorption within the visible spectrum, suggesting its suitability for various photonic and optoelectronic applications. Additionally, we calculated a wide range of optical characteristics, including the dielectric function, absorption coefficient, energy loss, reflectivity, refractive index, extinction coefficient, and optical conductivity, providing a comprehensive assessment of the material's optical properties.     

Hydrogen Peroxide Production of Individual Nanosecond Pulsed Discharges Submerged in Water of Elevated Conductivity

The production of hydrogen peroxide (H₂O₂) is a key parameter for the performance of pulsed discharges submerged in water utilized as advanced oxidation process. So far, any related assessment of the underlying mechanism was conducted for the application of several hundred discharges, which did not allow for a correlation with physical processes. Moreover, the production was rarely investigated depending on water conductivity as one of the most important parameters for the development of submerged discharges. Accordingly, hydrogen peroxide generation was investigated here for individual single discharge events instigated with 100 ns high-voltage pulses in water with three different conductivities and was associated with the discharge development, i. e. spatial expansion and dissipated electrical energy. The approach necessitated the improvement of an electrochemical flow injection analysis based on the reaction of Prussian blue with H₂O₂. Hydrogen peroxide concentrations were quadratically increasing with propagation time and stable for different water conductivities. H₂O₂ production per unit volume of a discharge was constant over time with an estimated rate constant of 3.2 mol ⋅ m⁻¹ s⁻¹, averaged over the crosssectional area of all discharge filaments. However, the individually dissipated energy increased with conductivity, hence, the production efficiency decreased from 6.1 g ⋅ kWh⁻¹ to 1.4 g ⋅ kWh⁻¹, which was explained by increased resistive losses within the bulk liquid.     

专业大类教学模式下公共数学课程体系的改革与设计

高等数学课程对实现高校的人才培养目标起着十分重要的作用.在当前按照专业大类招生并组织教学的情况下,高等数学的课程教学遇到了前所未有的问题与挑战.总结近年来我校高等数学课程体系和教学内容改革的实践经验,重新设计了高等数学课程的体系(模块),提出了进行了相应教学内容改革的意见,形成了整体课改方案,并分析了本方案所具有的特色.     

Matlab软件在高等数学教学中的应用

Matlab是当今最优秀的科技应用软件之一。基于Matlab在科学计算中的强大功能,本文探讨了Matlab软件在高等数学教学中的应用。针对高等数学中的极限、导数、积分、极值等问题,在教学中融入Matlab辅助计算,把所学理论转化为实践,不仅大大地提高了教学的实效性,并且为学生今后运用所学知识解决专业、实际等问题奠定了基础。     

Oscillation and Nonoscillation in Delay or Advanced Differential Equations and in Integrodifferential Equations

Some new oscillation and nonoscillation criteria are given for linear delay or advanced differential equations with variable coefficients and not (necessarily) constant delays or advanced arguments. Moreover, some new results on the existence and the nonexistence of positive solutions for linear integrodifferential equations are obtained.     

湖南生产服务业与先进装备制造业产业发展关系研究

以投入产出模型为基础,计算出湖南省生产服务业与先进装备制造业这两行业与各分行业的直接消耗系数、完全消耗系数、感应度系数和影响力系数.研究表明：先进装备制造业消耗力度大于生产服务业,但二者消耗水平均远低于发达国家,先进装备制造业对生产服务业的需求推动力和影响力较强,生产服务业的传统服务部门对产业发展推力较强,但资本、知识密集型生产服务部门作用正日益凸显,创新型部门则有待进一步发展.基于上述结论,提出了以生产服务业促进先进装备制造业发展,以先进装备制造业推动生产服务业发展的政策建议.     

高等数学“资源共享课”的实践

高等数学素质教育的一项重要内容是引导学生主动探求知识,自主归纳解决问题的方法,而"资源共享课"给学生提供了扩展视野、相互学习、展示自我的平台.这种组织课堂的方式有利于搞活课堂教学,提高学生数学素养及综合素质.