Determination of the electrochemical diffusion coefficient of methylene blue in SDS/n-C5H11OH/H2O system by non-probe microelectrode voltammetry

The diffusion coefficient of methylene blue (MB) is determined by the method of non-probe microelectrode voltammetry in sodium dodecyl sulfate (SDS)/n-C₅H₁₁OH/H₂O lyotropic liquid crystal system. The results obtained show that the diffusion coefficient of MB increases with water and n-pentanol contents in the microemulsions and the lyotropic liquid crystal but decreases with SDS content. The diffusion coefficient of SDS droplet in the microemulsions and the diffusion coefficient of SDS molecule in the lyotropic liquid crystal with MB all are less than those without MB. The magnitude order of the diffusion coefficient of MB is as follows: the coefficient in the oil-in-water (O/W) microemulsion is greater than the coefficient in the water-in-oil (W/O) microemulsion which is greater than the coefficient in the lamellar liquid crystal (LLC), which is also greater than the coefficient in the Hex.     

4p阶3度点传递图

一个图称为点传递图,如果它的全自同构群在它的顶点集合上作用传递.证明了一个4p(p为素数)阶连通3度点传递图或者是Cayley图,或者同构于下列之一;广义Petersen图P(10,2),正十二面体,Coxeter图,或广义Petersen图P(2p,k),这里k2≡-1(mod 2p).     

The impact of local resonance on the enhanced transmission and dispersion of surface resonances

We investigate the enhanced transmission through the square array of metallic coaxial annular apertures (MCAAs) in microwave frequency by varying the inner diameter of the apertures. The impact of local resonance is thoroughly embodied in the even-mode surface resonances, while the odd-mode surface resonances, invisible in measurements, are only scaled by periodicity. For MCAAs with smaller inner diameters, the transmission extrema are measured at specific incident angles matching the folded degenerate resonant states. The results are well understood in terms of the dispersion of surface resonances.     

Efficient synthesis of 1-R1-2-R-4,5-di(furan-2-yl)-1H-imidazoles and their luminescence properties

In this study, a series of 1-R₁-2-R-4,5-di(furan-2-yl)-1H-imidazole derivatives were synthesized in better yield 59.0%∼89.8% by the treatment of purified imidazole compounds with benzyl chloride or allyl chloride in the presence of sodium hydride, and were characterized by FT–IR, HRMS, ¹H NMR and ¹³C NMR spectroscopy. Furthermore, the luminescence properties of the synthesized products were investigated. It was found that N-substituted groups of imidazole have little influence on the absorption bands in a 0.1 N H₂SO₄ aqueous solution containing 0.5 mL of dissolved CH₃OH. However, the emission of some compounds in solution was sensitive to the polarity of the solvents.     

Order property and modulus of continuity of weak KAM solutions

For the Hamilton–Jacobi equation \(H(x,\partial _xu+c)=\alpha (c)\) with \(x\in \mathbb {T}^2\), it is shown in this paper that, for all \(c\in \alpha ^{-1}(E)\) with \(E>\min \alpha \), the elementary weak KAM solutions can be parameterized so that they are \(\frac{1}{3}\)-Hölder continuous in \(C^0\)-topology.     

电解质在超级电容器中的应用

超级电容器作为一种新型储能装置,因充放电快、功率密度高和循环寿命长的优异性能而引起了广泛的关注。电解质作为影响超级电容器性能的关键因素之一,其离子类型与尺寸、电化学窗口及电导率等性质对器件的工作电压、能量密度及循环寿命有着重要影响。针对近年来的研究现状,本文概述了超级电容器的储能原理、性能评估的关键参数及电解质在超级电容器中的应用研究进展。介绍了电解质的分类,包括水系电解质、有机电解质、离子液电解质和氧化还原电解质在内的液态电解质,及包括固态聚合物电解质、无机固态电解质及凝胶聚合物电解质在内的固态/准固态电解质。评述各类电解质的最新研发进展,讨论了电解质性质对超级电容器性能的影响,并阐明了超级电容器电解质的设计和优化方法。最后,分析了制备高性能电解质所面临的困难,并就其未来的研究方向作出了展望。     

农林废弃生物质吸附材料在水污染治理中的应用

环境污染问题已经成为人类社会可持续发展的巨大挑战之一,化工、冶炼及核燃料循环过程等排放的废水中含大量重金属离子、有机物及放射性核素等,若未经处理即排放会给环境带来了极大的危害。吸附法的效率高、操作简单、低成本且无副产物、可循环利用及无二次污染等优点使其成为废水处理的重要方法之一。由于农林废弃生物质成本低、来源丰富、绿色环保且可再生,以其为原料制备的吸附材料被广泛研究。本文主要针对以农林废弃生物质为原料制备的生物炭、纤维素及木质素为研究对象, 综述了生物炭的制备及改性方法、天然纤维素及木质素的改性方法及其在水污染治理中的应用现状。从原材料、制备工艺、改性方法等方面总结分析了吸附材料的性能对水中污染物吸附的影响,提出了生物质基吸附材料在水污染治理应用中所存在的问题,并展望了未来的发展方向。     

A novel method to fabricate superhydrophobic surfaces based on well-defined mulberry-like particles and self-assembly of polydimethylsiloxane

A superhydrophobic surface was obtained by combining application of CaCO₃/SiO₂ mulberry-like composite particles, which originated from violent stirring and surface modification, and self-assembly of polydimethylsiloxane. Water contact angle and sliding angle of the superhydrophobic surface were measured to be about 164 ± 2.5° and 5°, respectively. The excellent hydrophobicity is attributed to the synergistic effect of micro-submicro-nano-meter scale roughness (fabricated by composite particles) and the low surface energy (provided by polydimethylsiloxane). This procedure makes it possible for widespread applications of superhydrophobic film due to its simplicity and practicability.     

Platinum ion uptake by dendrimers: an NMR and AFM study

The reaction of generation 2 and generation 4 poly(amidoamine) (PAMAM) dendrimers with K2PtCl2 was studied by several NMR methods. The time dependency of the Pt(II) complexation was followed with 195Pt NMR for both dendrimers and the equilibrium product was further characterized with (1)H NMR, and indirectly detected 13C NMR, in the case of the generation 2 dendrimer. After 2 days, a black precipitate of Pt(0) was observed, half the original 195Pt signal was lost, and approximately 20% of the initial Pt(II) was coordinated to the tertiary and secondary nitrogens of the generation 2 dendrimer. The uptake of Pt(II) by the generation 4 dendrimer was much slower, consistent with the steric crowding of the surface groups on the generation 4 dendrimer compared to the more open generation 2. After 10 days, 80% of the Pt(II) was deep within the generation 4 dendrimer; the remaining 20% was unreacted or bound near the surface nitrogens of a single dendrimer. The location and time course of the platinum ion uptake by the dendrimers provides valuable insight into the formation of Pt(0) nanoparticles made in the presence of dendrimers as stabilizers, visualized by atomic force microscopy.