基于Ti3C2-MXene的太阳能界面水汽转换

水资源匮乏是现代化发展中面临的全球性问题,太阳能界面水汽转换(Interfacial Solar Steam Generation, ISSG)是一种高效、绿色、低成本进行海水淡化和废水处理的方法。ISSG使用绿色的太阳能作为热源,通过光热转换并将热限制在水气界面上以高效产生蒸气,然后经过冷凝收集获得清洁水。设计和构筑具有强光吸收的光热转换材料是ISSG的技术核心。Ti₃C₂-MXene是一种新型二维碳化钛材料,具有比表面积大、水分散性好和光热转换效率高等优点,在ISSG领域具有巨大的应用潜力。本文介绍了ISSG技术和MXene,总结了光热转换材料的设计原则,论述了Ti₃C₂-MXene复合材料在ISSG领域的研究进展,其中包括二维MXene薄膜、三维MXene气凝胶和水凝胶、生物基-MXene复合材料的构筑和性能等,并分析了Ti₃C₂-MXene所面临的挑战和发展前景。     

Co3O4 Decorated Ti/TiO2 Nanotubes for Photogenerated Cathodic Protection of 304 Stainless Steel

The Co₃O₄ decorated TiO₂ nanotube arrays(NTAs) coatings are fabricated by the combination of anodization and impregna-ting methods. It is found that the introduction of Co₃O₄ can reduce the diffraction intensity of (101) plane of the TiO₂ and accelerate the separation of photogenerated electron/hole pairs. In addition, the open circuit potential(OCP) and the corrosion potential of 304 stainless steel(304SS) with or without Co₃O₄ decorated TiO₂ NTAs were measured under visible light, which indicated the 304SS coupled with Co₃O₄ decorated TiO₂ NTAs had better anticorrosion performance than that of the 304SS or the 304SS coupled with pure TiO₂ NTAs. The enhancement of the cathodic protection performance of the Co₃O₄ decorated TiO₂ NTAs can be ascribed to the matched energy levels and strong interaction between Co₃O₄ and TiO₂ NTAs, and the improvement of light absorption.     

MXene-碳黑/硫复合材料在锂硫电池一体式电极的研究

锂硫电池的实际能量密度不高和多硫化物（LiPSs）的穿梭效应等问题严重影响了该电池的实际应用。本文通过将二维的Ti₃C₂T_x Mxene纳米片与碳黑/硫（CB/S）材料进行混合,制备了Ti₃C₂T_x-CB/S正极材料并将其涂覆在商业隔膜（PP）上,最终获得了Ti₃C₂T_x-CB/S-PP一体式电极并用于锂硫电池。利用Ti₃C₂T_x纳米片对CB/S进行修饰,不仅能提高活性物质硫的导电性,还能对扩散的LiPSs进行物理阻挡和化学吸附。而一体式电极的设计有利于提高电池的能量密度。恒流充放电测试结果表明,Ti₃C₂T_x-CB/S-PP电极在0.1 C电流下的初始放电容量为1028.8 mAh·g^-1,高于不含Ti₃C₂T_x的CB/S-PP电极的896.8 mAh·g^-1。Ti₃C₂T_x-CB/S-PP电极还展示出了比基于传统铝箔集流体的Ti₃C₂T_x-CB/S-Al电极更好的循环稳定性,前者在0.5 C下400圈长循环测试中的每圈衰减率为0.072%,而后者则为更高的0.10%。本文利用Ti₃C₂T_x-CB/S构建一体式电极的策略为实现高性能和高能量密度的锂硫电池提供了新的研究方向。     

溶胶-凝胶法制备Pb(Zr1?xTix)O3复合梯度薄摸以及介电与热释电特性

"在Pt/Ti/SiO2/Si基片上用溶胶-凝胶法生长制备了PZT(Pb(Zr1-xTix)O3)复合梯度铁电薄膜． 薄膜最终结构由6层组成,"向上"梯度薄膜在Pt底电极上的第一层从PbZrO3开始,顶层是PZT(50/50),即第一层是PbZrO3,第二层PZT90/10 (10%Ti),第三层是PZT80/20,第四层PZT70/30,第五层PZT60/40,第六层PZT50/50．每一层与此相反的是"向下"梯度PZT薄膜．用X射线衍射、俄歇电子能谱和阻抗分析来研究梯度薄膜的结构与介电特性．600     

混合熔盐法低温合成Sm2Ti2S2O5及其光催化分解水产氢

以TiO2、TiS2及Sm2O3为前驱体,分别加入LiCl-KCl与LiCl-CsCl的最低共熔混合物作为熔盐,在较低温度下成功合成了Sm2Ti2S2O5(STSO)颗粒。通过对比不同温度下所制备产物的X射线衍射图,首次表明STSO的热力学结晶温度在520℃左右,远低于之前报道的650℃的最低合成温度。扫描电子显微镜照片显示,采用2种混合熔盐制备的STSO都呈片状形貌;同一合成温度下,采用LiCl-CsCl熔盐制备的STSO的厚度小于LiCl-KCl所得产物。采用出射光波长大于420 nm的氙灯作为光源,在含有Na2S-Na2SO3空穴牺牲剂的溶液中,所制备的STSO颗粒表现出最高35μmol·h-1的光催化分解水产氢活性以及20 h以上的产氢稳定性。     

Spin gapless semiconductor like Ti2MnAl film as a new candidate for spintronics application

A novel Heusler ferrimagnet Ti₂MnAl film has been grown on Si(001) substrate using magnetron sputtering. Characteristics of its magnetic and transport properties reveal the spin‐gapless‐semiconductor (SGS) nature of the stoichiometric Ti₂MnAl, in agreement with theoretical prediction. The as‐grown SGS‐like Ti₂MnAl film demonstrated high Curie temperature, nearly compensated ferrimagnetic properties with small coercivity and low magnetization. It also showed semiconductor‐like behavior at room temperature allowing good compatibility with commercial Si‐based semiconductor. In this regards, Ti₂MnAl film is a potential candidate material for spintronics application, especially for the minimization of energy consumption of device. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)     

Surface modification of pure titanium by pulsed electron beam

The microstructure, hardness and corrosion resistance of commercially pure Ti treated by low energy high current pulsed electron beam (LEHCPEB) have been investigated. The thin near-surface melted layer rapidly solidified into β and subsequently transformed into ultrafine α′ martensite. This has led to a drastic improvement of the corrosion properties and a significant increase (more than 60%) in hardness of the top surface.     

Study of Optically Stimulated Luminescence of LiF:Mg,Ti for beta and gamma dosimetry

Modern advances in radiation medicine – radiodiagnosis, radiotherapy and interventional radiography – each present dosimetry challenges for the medical physicist that did not exist previously. In all of these areas a constant balance has to be made between the treatment necessary to destroy the tumor and the unnecessary exposure of healthy tissue. Innovative applications of OSL dosimetry are now appearing in each of these areas to help the medical physicist and oncologist design the most effective, and least deleterious, treatment for their patients. High sensitivity, precise delivery of light, fast readout times, simpler readers and easier automation are the main advantages of OSL in comparison with TLD.This work aimed to study the application of OSL technique using lithium fluoride dosimeters doped with magnesium and titanium (LiF:Mg,Ti) for application in beta and gamma dosimetry.     

钛扩散铌酸锂矩形波导中的双折射耦合对传播常数的影响

 从亥姆霍兹方程出发，得到了各向异性光波导在弱导近似下的耦合模理论。耦合系数包括偏振耦合项和双折射耦合项。并用马卡提里近似下的模式作为零级近似。用一级微扰法计算了折射率渐变分布的钛扩散铌酸锂矩形波导的传播常数。在给定参数的情况下，得到双折射项引起的传播常数的改变约为主微扰项的3%，因此双折射耦合对钛扩散铌酸锂矩形波导的性能影响不可忽略，这对设计和分析与它相关的光波导器件具有指导意义。