Superparamagnetic Twist‐Type Actuators with Shape‐Independent Magnetic Properties and Surface Functionalization for Advanced Biomedical Applications

Directed nanoparticle self‐organization and two‐photon polymerization are combined to enable three‐dimensional soft‐magnetic microactuators with complex shapes and shape‐independent magnetic properties. Based on the proposed approach, single and double twist‐type swimming microrobots with programmed magnetic anisotropy are demonstrated, and their swimming properties in DI‐water are characterized. The fabricated devices are actuated using weak rotating magnetic fields and are capable of performing wobble‐free corkscrew propulsion. Single twist‐type actuators possess an increase in surface area in excess of 150% over helical actuators with similar feature size without compromising the forward velocity of over one body length per second. A generic and facile combination of glycine grafting and subsequent protein immobilization exploits the actuator's increased surface area, providing for a swimming microrobotic platform with enhanced load capacity desirable for future biomedical applications. Successful surface modification is confirmed by FITC fluorescence.     

Magnetization dynamics and related phenomena in semiconductors with ferromagnetism

We review ferromagnetic resonance (FMR) and related phenomena in the ferromagnetic semiconductor (Ga,Mn)As and single crystalline Fe/GaAs (001) hybrid structures. In both systems, spin-orbit interaction is the key ingredient for various intriguing phenomena.     

高温氦气环境中石墨的水蒸气氧化特性模拟研究

在正常运行工况下高温气冷堆内石墨材料的氧化对石墨结构材料的服役时间有重要影响.主要介绍高温气冷堆燃料元件氦气孔道内石墨材料与水蒸气发生氧化反应的模拟.该模型使用COMSOL软件进行建模,采用k-ε模型模拟冷却剂的流动,使用Langmuir-Hinshelwood方程描述石墨与水蒸气的化学反应.使用该模型计算了冷却剂管道温度分布为线性、水蒸气压力低于1 Pa的氧化情况.计算结果表明,在堆芯底部氧化主要发生在表面,石墨材料转化率高于8%的厚度约1 mm.     

Anwendungen für Mehrphasen-CFD am Fahrzeugexterieur

Forschung im Ingenieurwesen - In der Automobilindustrie werden einphasige Strömungssimulationen seit vielen Jahren zur Aerodynamik- und Aeroakustikentwicklung eingesetzt. Sie gewähren...