滇皂荚开发现状与前景

滇皂荚是产于云南的皂荚属特有种类,其在医药、绿化、食品工业、化工等方面有广泛的应用前景。本文综述了滇皂荚在各个方面的利用价值,以及相关开发研究的现状,并从生态和经济相结合的角度对滇皂荚资源的开发利用前景进行了探讨。     

顶空固相微萃取-气相色谱/质谱法分析野藿香不同部位挥发油化学成分

采用顶空固相微萃取法(headspace solid-phase micro-extraction,HS-SPME)提取野藿香中不同部位的挥发油,通过气相色谱-质谱法与Kovats色谱保留指数相结合进行定性定量分析,以峰面积归一化法计算各组分的相对含量。结果表明:在野藿香的茎、叶和花3个部位中分别鉴定出74、105种和85种化合物,分别占挥发油总峰面积的97.34%、98.80%和97.96%,其中在茎中主要成分是乙酸橙花酯(5.63%)、β-石竹烯(17.32%)、α-佛手柑油烯(7.56%)、反式-β-金合欢烯(10.2%)和氧化石竹烯(5.21%);在叶中主要是Z-柠檬醛(11.64%)、香叶醛(16.35%)、乙酸橙花酯(8.44%)、β-石竹烯(13.08%)、反式-β-金合欢烯(10.88%)和氧化石竹烯(8.34%);而在花中主要是Z-柠檬醛(21.49%)、香叶醛(27.5%)、乙酸橙花酯(9.99%)、β-石竹烯(5.47%)和反式-β-金合欢烯(10.11%),且相对含量有显著差异。     

Lithiophilic MXene-Guided Lithium Metal Nucleation and Growth Behavior

The positive effects of a lithiophilic substrate on the electrochemical performance of lithium metal anodes are confirmed in several reports, while the understanding of lithiophilic substrate-guided lithium metal nucleation and growth behavior is still insufficient. In this study, the effect of a lithiophilic surface on lithium metal nucleation and growth behaviors is investigated using a large-area Ti₃C₂T_x MXene substrate with a large number of oxygen and fluorine dual heteroatoms. The use of the MXene substrate results in a high lithium-ion concentration as well as the formation of uniform solid–electrolyte-interface (SEI) layers on the lithiophilic surface. The solid–solid interface (MXene-SEI layer) significantly affects the surface tension of the deposited lithium metal nuclei as well as the nucleation overpotential, resulting in the formation of uniformly dispersed lithium nanoparticles ( ≈ 10–20 nm in diameter) over the entire MXene surface. The primary lithium nanoparticles preferentially coalesce and agglomerate into larger secondary particles while retaining their primary particle shapes. Subsequently, they form close-packed structures, resulting in a dense metal layer composed of particle-by-particle microstructures. This distinctive lithium metal deposition behavior leads to highly reversible cycling performance with high Columbic efficiencies >  99.0% and long cycle lives of over 1000 cycles.     

超疏水涂层的制备及其在金属防腐领域的应用研究进展

由于超疏水材料表面的特殊结构和高疏水性，当其应用在金属表面时，能有效阻止金属基材与腐蚀介质的接触，从而大幅度地提高金属材料的耐腐蚀性能及使用寿命。首先对固体表面浸润理论以及超疏水材料的基础理论进行阐述；然后，介绍了在金属材料表面制备超疏水涂层的常用工艺技术；最后，总结并讨论了超疏水表面涂层在钢、铝和镁等金属材料上的近期发展与应用状况。     

Subdivision based isogeometric analysis for geometric flows

We present a new isogeometric analysis (IGA) approach based on extended Loop subdivision scheme for solving various geometric flows defined on subdivision surfaces. The studied flows include the second-order, fourth-order, and sixth-order geometric flows, such as averaged mean curvature flow, constant mean curvature flow, and minimal mean-curvature-variation flow, which are generally derived by minimizing the associate energy functionals with $L^2$-gradient flow respectively. The geometric flows are discretized by means of subdivision based IGA, where the finite element space is formulated by the limit form of the extended Loop subdivision for different initial control meshes. The basis functions, consisting of quartic box-splines corresponding to each subdivided control mesh, are utilized to represent the geometry exactly. For the cases of the evolution of open surfaces with any shape boundary, high-order continuous boundary conditions derived from the mixed variational forms of the geometric flows should be implemented to be consistent with the isogeometric concept. For time discretization, we adopt an adaptive semi-implicit Euler scheme. By several numerical experiments, we study the convergence behaviors of the proposed approach for solving the geometric flows with high-order boundary conditions. Moreover, the numerical results also show the accuracy and efficiency of the proposed method.     

Reducing resistance and curing temperature of silver pastes containing nanowires

Low temperature silver pastes can be widely applied on thin-film switch, flexible printing line and touch screen. In this article, we investigated printability and conductivity of silver pastes with silver wires of different diameters and content, and the conductivity of the silver pastes cured at different temperatures filled with different types silver powders and silver wires. The sheet resistance of silver pastes cured at 100 °C with Ag1 powders and Ag2 powders filled with 10 wt% silver wires of 100 nm diameters is 21.93?±?1.63 and 23.16?±?1.44 Ω/□, which is lower than the same samples cured at 135 °C without silver wire fillers. Tap density of Ag1 and Ag2 powders mixed with silver nanowires is higher than that of Ag3 powders mixed with nanowires, due to a higher filling ratio of Ag1 and Ag2 powders with silver nanowires. SEM results show silver pastes filled with Ag1 and Ag2 powders formed network when silver nanowires were added.     

Toward High-Performance Dihydrophenazine-Based Conjugated Microporous Polymer Cathodes for Dual-Ion Batteries through Donor–Acceptor Structural Design

Recent studies have demonstrated that dihydrophenazine (Pz) with high redox-reversibility and high theoretical capacity is an attractive building block to construct p-type polymer cathodes for dual-ion batteries. However, most reported Pz-based polymer cathodes to date still suffer from low redox activity, slow kinetics, and short cycling life. Herein, a donor–acceptor (D–A) Pz-based conjugated microporous polymer (TzPz) cathode is constructed by integrating the electron-donating Pz unit and the electron-withdrawing 2,4,6-triphenyl-1,3,5-triazine (Tz) unit into a polymer chain. The D–A type structure enhances the polymer conjugation degree and decreases the band gap of TzPz, facilitating electron transportation along the polymer skeletons. Therefore the TzPz cathode for dual-ion battery shows a high reversible capacity of 192 mAh g⁻¹ at 0.2 A g⁻¹ with excellent rate performance (108 mAh g⁻¹ at 30 A g⁻¹), which is much higher than that of its counterpart polymer BzPz produced from 1,3,5-triphenylbenzene (Bz) and Pz (148 and 44 mAh g⁻¹ at 0.2 and 10 A g⁻¹, respectively). More importantly, the TzPz cathode also shows a long and stable cyclability of more than 10 000 cycles. These results demonstrate that the D–A structural design is an efficient strategy for developing high-performance polymer cathodes for dual-ion batteries.