一种硅微机械陀螺制造方法研究

给出了一种硅微机械陀螺制造方法,该方法可适用于各种不同的微机电系统(MEMS)器件,包括加速度计、剪切应力传感器及MEMS光开关等。利用该方法制备了硅微机械陀螺,并给出了该陀螺的性能测试结果。同时分析了利用该方法制备各种不同器件时,工艺流程对器件性能的影响,重点讨论了硅-玻璃阳极键合、减薄工艺及深刻蚀所形成的侧壁质量,包括侧壁垂直度、侧壁杂质等因素对器件性能的影响。     

Patterning Flexible Substrates Using Surface Relief Structures in Azobenzene Functionalized Polymer Films

A novel method for maskless micro-patterning of polymeric substrates is presented. First, an azobenzene functionalized polymer film is spin-coated on a Poly (ethylene terephthalate) (PET) sheet. Then surface relief structures are optically inscribed on the polymer film by interference of laser beams. The patterned azobenzene functionalized film is then etched in the plasma chamber such that the gratings are transferred to the PET substrate. Finally, any remaining azobenzene functionalized polymer is dissolved away using an appropriate solvent. This method of patterning can be broadly applied to a variety of flexible/polymeric substrates and the resolution is not limited by the substrate thermo-mechanical properties.     

Low‐Transition‐Temperature Mixtures (LTTMs): A New Generation of Designer Solvents

A new generation of designer solvents emerged in the last decade as promising green media for multiple applications, including separation processes: the low‐transition‐temperature mixtures (LTTMs). They can be prepared by mixing natural high‐melting‐point starting materials, which form a liquid by hydrogen‐bond interactions. Among them, deep‐eutectic solvents (DESs) were presented as promising alternatives to conventional ionic liquids (ILs). Some limitations of ILs are overcome by LTTMs, which are cheap and easy to prepare from natural and readily available starting materials, biodegradable, and renewable.     

Deep eutectic solvents and glycerol: a simple,environmentally benign and efficient catalyst/reaction media for synthesis of N-aryl phthalimide derivatives

Abstract

Deep eutectic solvents (DES) and glycerol have been successfully employed as efficient catalysts/reaction media in the synthesis of N-aryl phthalimide derivatives from phthalic anhydride and primary aromatic amines. The DES prepared from choline chloride and malonic acid proved to be an efficient catalyst whereas glycerol and the DES of choline chloride and urea played a dual role of catalyst and solvent. These mixtures are biodegradable, nontoxic, and cost-effective thereby providing a good industrial alternative to conventional methods. These methods gave products in moderate to high yields with good recyclability of catalyst/solvent at least up to five consecutive runs.     

Natural deep eutectic solvents as new potential media for green technology

Developing new green solvents is one of the key subjects in Green Chemistry. Ionic liquids (ILs) and deep eutectic solvents, thus, have been paid great attention to replace current harsh organic solvents and have been applied to many chemical processing such as extraction and synthesis. However, current ionic liquids and deep eutectic solvents have still limitations to be applied to a real chemical industry due to toxicity against human and environment and high cost of ILs and solid state of most deep eutectic solvents at room temperature. Recently we discovered that many plant abundant primary metabolites changed their state from solid to liquid when they were mixed in proper ratio. This finding made us hypothesize that natural deep eutectic solvents (NADES) play a role as alternative media to water in living organisms and tested a wide range of natural products, which resulted in discovery of over 100 NADES from nature. In order to prove deep eutectic feature the interaction between the molecules was investigated by nuclear magnetic resonance spectroscopy. All the tested NADES show clear hydrogen bonding between components. As next step physical properties of NADES such as water activity, density, viscosity, polarity and thermal properties were measured as well as the effect of water on the physical properties. In the last stage the novel NADES were applied to the solubilization of wide range of biomolecules such as non-water soluble bioactive natural products, gluten, starch, and DNA. In most cases the solubility of the biomolecules evaluated in this study was greatly higher than water. Based on the results the novel NADES may be expected as potential green solvents at room temperature in diverse fields of chemistry.     

Regular arrays of triangular‐microstructure formed on silicon (111) surface via ultrafast laser irradiation in KOH solution

The regular micrometer‐scale triangular arrays were formed using ultrafast femtosecond laser irradiation on (111) surface of silicon wafer immersed in KOH solution (0.1 g/ml). At low laser fluence, the resulting surface is covered by triangular pits microstructures, whereas at high laser fluence, the structures are transformed to multilayer‐triangular stacks‐microstructures. The number of triangular stacks layer increased as the laser fluence increased. The formation of triangle microstructure arrays depends on both silicon surface crystallographic orientation and the concentration of KOH solution. Either for lower KOH solution concentration (0.02 g/ml) or other silicon crystallographic orientation, triangle arrays cannot be obtained. We attribute the formation of triangular microstructure arrays to the laser‐assisted chemical etching process. Copyright © 2013 John Wiley & Sons, Ltd.     

基于深度学习理论的有机合成课程教学改革

有机合成既是有机化学学习中的一个独立构成部分,也是安排于有机化学课程之中的重要学习主题。在目前的有机合成课程教学中,教师的自觉性引导不足,学生容易陷入浅层学习状态,导致教学效果不佳。结合有机化学学科特点,从有机合成课程教学现状出发,围绕深度学习教学设计的四要素——深度学习目标、挑战性学习主题、深度学习活动、持续性评价,以典型的教学片段为例阐述深度学习理论在教学实践中的应用,为相关教学工作提供参考。     

基于深度学习的“实验方案设计”主题式复习教学——以“阿司匹林的制备和提纯”为例

针对实验方案设计题的得分率分析和教学现状,基于课程标准、教材、真题和文献研究,构建“阿司匹林的制备和提纯”深度学习主题模型。通过设计制备和提纯阿司匹林的实验方案,构建实验方案设计的思维模型,并以制备七水合硫酸锌为例内化思维模型,在解决真实、复杂的问题过程中实现核心知识结构化,生成指向深度学习的主题式复习教学流程。     

低共熔溶剂用于高效可逆捕集二氧化碳的研究

本文通过一步合成法合成了四种不同摩尔比的四乙基氯化胺-乙醇胺低共熔溶剂（TEAC-MEA DES）。红外光谱表征分析表明该DES是依靠氢键作用而形成的;DES的热稳定性高于MEA,且随着MEA的比例的增加而降低;对不同比例的DES进行了四次循环CO₂吸收-解吸实验,发现其吸收容量几乎不变,重复使用性能较好。在不同温度下计算了化学平衡常数,lnK对1/T线性拟合结果表明DES吸收CO₂的反应焓是负值,即吸收CO₂的反应是放热过程。该DES在吸收CO₂方面具有很大的潜力。