A novel conjugated porous polymer based on triazine and imide as cathodes for sodium storage

Organic electrode materials have attracted more and more attention for sodium-ion batteries (SIBs) that are regarded as one of the most promising alternatives of lithium-ion batteries, because they can endure the storage of large sodium ions (with a larger radius than that of lithium ions) without obvious volume change. Herein, we report a novel conjugated porous polymer (TPIP) based on triazine and imide as cathodes material for SIBs. TPIP has abundant redox-active sites, good thermal stability (400°C) and large specific surface area (306 m² g⁻¹). As a result, TPIP electrode delivered a specific capacity of 120 mAh g⁻¹ after 50 cycles at a current density of 0.1 A g⁻¹ and 85 mAh g⁻¹ after 150 cycles at a current density of 1.0 A g⁻¹. Ex-situ X-ray photoelectron spectra and Fourier transform infrared spectra showed that the TPIP electrodes reversibly stored three sodium ions per unit through the triazine rings and half of the carbonyl groups. These results deepen our understanding of charge storage mechanisms of polymers with triazine and imide units and will provide guidance for the future design of electrode materials for high-performance SIBs.     

Stable and oscillating solitons of $$\pmb {\mathcal {PT}}$$ -symmetric couplers with gain and loss in fractional dimension

Nonlinear Dynamics - Families of coupled solitons of $$\mathcal {PT}$$ -symmetric physical models with gain and loss in fractional dimension and in settings with and without cross-interactions...     

基于介孔碳的电化学酪氨酸酶生物传感器法测定水体中的苯酚及高效液相色谱法评价

采用新型的介孔碳材料作为固载酪氨酸酶的检测平台构建生物传感器,应用于水体环境中苯酚污染物的检测,并通过高效液相色谱法对电化学酪氨酸酶生物传感器法的准确性进行了评价。研究表明,介孔碳的"空间限制效应"能够防止酪氨酸酶(三维尺寸为6.5 nm×9.8 nm×5.5 nm)体外去折叠失活。基于介孔碳材料构建的电化学酪氨酸酶生物传感器在苯酚污染物检测方面显示了优良的性能,其重现性、灵敏度、稳定性、选择性以及检出限均比较令人满意。基于介孔碳的电化学酪氨酸酶生物传感器对苯酚污染物的检出限达到20 nmol/L,线性范围为0.1~10 μmol/L。采用基于介孔碳的电化学酪氨酸酶生物传感器和高效液相色谱法对实际水样品进行测定结果比对,结果表明该生物传感器方法检测结果准确、有效,适合于苯酚污染物突发污染事件的应急检测。     

Barotropic instability of shear flows

We consider barotropic instability of shear flows for incompressible fluids with Coriolis effects. For a class of shear flows, we develop a new method to find the sharp stability conditions. We study the flow with Sinus profile in details and obtain the sharp stability boundary in the whole parameter space, which corrects previous results in the fluid literature. Our new results are confirmed by more accurate numerical computation. The addition of the Coriolis force is found to bring fundamental changes to the stability of shear flows. Moreover, we study dynamical behaviors near the shear flows, including the bifurcation of nontrivial traveling wave solutions and the linear inviscid damping. The first ingredient of our proof is a careful classification of the neutral modes. The second one is to write the linearized fluid equation in a Hamiltonian form and then use an instability index theory for general Hamiltonian partial differential equations. The last one is to study the singular and nonresonant neutral modes using Sturm-Liouville theory and hypergeometric functions.     

用DCG制作彩色反射全息图的研究

本文介绍了采用重铬酸盐明胶制作彩色全息的方法,并对影响彩色全息图的因素进行了研究,通过选择适宜的实验参数、实验条件及显影处理工艺,获得了满意的彩色反射全息图.     

岩溶区土洞发育机制的分析

岩溶区地下水或地表水的活动 ,将对土层产生潜蚀作用及崩解作用 ,进而形成土洞。真空吸蚀作用 ,有利于土洞的发育扩大。地下水位的变化 ,将使土洞周围土体的应力状态发生改变 ,并有可能导致土洞周围土体产生塑性破坏 ,使土洞进一步扩大甚至塌陷.     

在电厂贮灰场上修建10．50米高灰坝的一个成功实例

本文以工程实践,论述了电厂废料粉煤灰渣这种特殊类土的形成,物理力学特征,以及应用其修建我国最高的灰坝的经验。这个灰坝经过三年的安全贮灰运行验证,证明是成功的,创造了应用电厂粉煤灰渣修建国内最高灰坝,并安全贮灰的新纪录。     

Pd-catalyzed oxidative olefination of arenes with olefins via C–H activation: Retention of the leaving group

Russian Journal of Applied Chemistry - Pd-catalyzed direct oxidative olefination of arenes with olefins via C–H activation is described in the absence of any chelating directing groups. For...     

Resonator effects of Ar<Stack><Subscript>2</Subscript><Superscript>+</Superscript></Stack> ionic excimer pumped by electron beam

The third continuum of argon from 200 to 270 nm is obtained by electron beam pumping argon. With the front mirror and the rear mirror, the resonator effects are observed at 240 and 220 nm. Compared with the intensity of fluorescence, the intensity near 240 nm increases more than 10 times when the resonator is formed. In order to explain the origin of the continuum, the kinetic model on Ar₂⁺ and Ar₂²⁺ ionic excimers pumped by electron beam is built and calculated. Based on the theoretical results, the Ar₂⁺ ionic excimer should be responsible for the continuum around 240 nm.     

磺化间规聚苯乙烯和间规聚苯乙烯的非等温结晶动力学

对磺化度分别为 1 6 0mol% ,3 0 5mol% ,4 41mol%的磺化间规聚苯乙烯和间规聚苯乙烯的非等温结晶动力学进行了研究 ,用DSC测试了四种样品的非等温结晶过程 ,对所得数据分别用Mandelkern方法和莫志深方法进行了处理 ,发现磺化间规聚苯乙烯和间规聚苯乙烯的非等温结晶动力学参数差别较大 ,说明磺酸基团的引入对sPS结晶行为有较大的影响 ,磺酸基团之间的氢键相互作用使SsPS的结晶速率降低 ,结晶度减小 .此外 ,SsPS和sPS的Avrami指数n值均在 2～ 3之间 ,且为非整数 ,说明它们主要是以混合成核的方式结晶 .SsPS的成核与生长活化能ΔE值高于sPS的 ,并且随磺化度的增加而递增 ,sPS的ΔE值为 2 40 5 0kJ/mol,磺化度为 1 6 0mol% ,3 0 5mol%和 4 41mol%的SsPS的ΔE值分别为 2 5 1 70kJ/mol,2 72 33kJ/mol和2 90 79kJ/mol.