Medium effect on dielectric relaxation behaviors of 4A zeolite bulk dispersion system

Dielectric spectra of 4A zeolite particles bulked in deionized water (4A/W) or cyclohexane (4A/C) were measured respectively under different temperatures, and two dielectric relaxations were found in both of 4A/W and 4A/C. Because of existence of water molecules in pores, both low and high frequency relaxation times (τ_LFR and τ_HFR) of 4A/Wdecreasedmore sharply than 4A/C with increasing temperature. According to the temperature dependence of τ_LFR and τ_HFR, the activation energies of Na⁺ interacting with framework under hydrated and dehydrated environments were calculated respectively, and the original properties of Na⁺ in dehydrated zeolite were obtained by analyzing the dielectric properties of 4A/C. Furthermore, a transient state of Na⁺ motion with temperature was found in 4A/C system.     

强化基础引导创新——核磁共振实验教学体系建设*

面对不同年级本科生和研究生设计了由浅入深、梯度渐进的核磁共振实验教学体系,利用实验教学全面介绍了核磁共振这一重要的分析手段,结合线上教学、课堂互动等新颖的教学模式,加深对重要知识点的认识和了解,与理论教学有机结合,取得了良好的教学效果。     

基于PbI2的有机-无机杂化化合物的合成和晶体结构

合成得到了2个新的有机-无机杂化化合物{（4-CH₃-Bz-4-Ph-Py）[PbI₃]}_n（1）（其中4-CH₃-Bz-4-Ph-Py是4-甲基苄基-4-苯基吡啶阳离子）和{（4-CF₃-Bz-4-Ph-Py）[PbI₃]}_n（2）（其中4-CF₃-Bz-4-Ph-Py是4-三氟甲基苄基-4-苯基吡啶阳离子）。对化合物1和2进行了元素分析、粉末X射线衍射等表征,并利用X射线单晶衍射测定了它们的单晶结构。化合物1属于正交晶系,P2₁2₁2空间群;化合物2与1同构。结构研究表明,化合物1和2中,铅碘八面体通过共边连接方式,形成[Pb₃I₉]_n三链,有机阳离子填充在无机碘化铅链空隙中。     

Dynamic Analysis of an Infinite Cylindrical Hole in a Saturated Poroelastic Medium

In this paper, the dynamic response of an infinite cylindrical hole embedded in a porous medium and subjected to an axisymmetric ring load is investigated. Two scalar potentials and two vector potentials are introduced to decouple the governing equations of Biot’s theory. By taking a Fourier transform with respect to time and the axial coordinate, we derive general solutions for the potentials, displacements, stresses and pore pressures in the frequency-wave-number domain. Using the general solutions and a set of boundary conditions applied at the hole surface, the frequency-wave-number domain solutions for the proposed problem are determined. Numerical inversion of the Fourier transform with respect to the axial wave number yields the frequency domain solutions, while a double inverse Fourier transform with respect to frequency as well as the axial wave number generates the time-space domain solution. The numerical results of this paper indicate that the dynamic response of a porous medium surrounding an infinite hole is dependant upon many factors including the parameters of the porous media, the location of receivers, the boundary conditions along the hole surface as well as the load characteristics.     

Novel identification approach for nonlinear systems with hysteresis

Nonlinear Dynamics - A new identification approach for a nonlinear system with hysteresis, namely a cascading Bouc–Wen hysteresis model with linear dynamics, is proposed in this study. The...     

新型金属蜂窝板燃烧器的高效燃烧现象分析

新型金属蜂窝板燃烧器是通过采用双层或多层金属薄片制成,能有效地解决普通燃气灶具燃烧器存在的不足,使产品结构更加合理完善,性能更加稳定可靠,能效更加优越。本文以红外燃气灶具的核心部件—新型金属蜂窝板燃烧器为研究对象,利用红外摄像仪对红外燃气灶具和普通燃气灶具进行了对比研究。结果表明,红外燃气灶的火焰集中,温度分布均匀,燃烧效率比普通燃气灶高12.7%。     

A Novel d-f Heterometallic CdII-EuIII Metal-organic Framework as a Sensitive Luminescent Sensor for the Dual Detection of Ronidazole and 4-Nitrophenol

A novel three-dimensional (3D) d-f heterometallic metal-organic framework (MOF) formulated as [EuCd_1.5L₂(H₂O)₃] · 2H₂O ( 1 ) [H₃L = 5-(4-(tetrazol-5-yl)phenyl)isophthalic acid] was successfully synthesized and characterized. Structural analysis displays that 1 features a 3D (3, 12)-connected framework constructed by [Eu₂Cd₃(tetrazole)₄(COO)₈] units. The powder X-ray diffraction measurement of 1 immersed in different solvents reveals that 1 possess good solvent stability. It is worth noting that 1 displays highly selective detection for ronidazole (RDZ) and 4-nitrophenol (4-NP) through luminescence quenching. The possible mechanism of luminescent sensing is also well discussed.     

锌掺杂对TiO2染料敏化电池光阳极中电荷俘获态分布及电子复合过程的影响

基于瞬态光电压和瞬态光电流技术研究了锌掺杂的TiO2染料敏化太阳能电池中电子复合及传输的动力学行为.通过实验获得了不同阳极掺杂条件下的电子复合时间常数与电子收集时间常数,考察了锌掺杂对电池阳极材料导带能级和电子俘获态的影响.研究结果表明,锌的掺杂在提高TiO2导带能级的同时延长了俘获态电子的复合时间常数,从而大大提高了电池的开路电压.