High‐Density Periodically Ordered Magnetic Cobalt Ferrite Nanodot Arrays by Template‐Assisted Pulsed Laser Deposition

A novel nanopatterning method using pulsed laser deposition through an ultrathin anodic aluminium oxide (AAO) membrane mask is proposed to synthesize well‐ordered nanodot arrays of magnetic CoFe₂O₄ that feature a wide range of applications like sensors, drug delivery, and data storage. This technique allows the adjustment of the array dimension from ～35 to ～300 nm in diameter and ～65 to ～500 nm in inter‐dot distance. The dot density can be as high as 0.21 Terabit in.^?2. The microstructure of the nanodots is characterized by SEM, TEM, and XRD and their magnetic properties are confirmed by well‐defined magnetic force microscopy contrasts and by hysteresis loops recorded by a superconducting quantum interference device. Moreover, the high stability of the AAO mask enables the epitaxial growth of nanodots at a temperature as high as 550 °C. The epitaxial dots demonstrate unique complex magnetic domains such as bubble and stripe domains, which are switchable by external magnetic fields. This patterning method creates opportunities for studying novel physics in oxide nanomagnets and may find applications in spintronic devices.     

Microdomain Transformations in Mosaic Mesocrystal Thin Films

An easy design route via simple evaporation is reported for macroscopic mosaic thin films comprising the quaternary system of dl ‐lysine·HCl, poly(acrylic acid), water, and EtOH. By depositing droplets of the quaternary dispersions onto hydrophilic cover slips, the formation of macroscopic crack‐free mosaic mesocrystal thin films are produced. The formation follows a multistage crystallization process, which includes the formation of a polymer‐induced liquid‐precursor (PILP) phase, the formation of spherulitic thin films, and the recrystallization of mosaic mesocrystal thin films. A slow cooling rate is noted to be beneficial for the mesocrystal thin films, enabling the films to be crack‐free and to display low surface roughness at the nanoscale.     

Biomimetic Hydroxyapatite Crystallization in Gelatin Nanoparticles Synthesized Using a Miniemulsion Process

Here, we report a novel biomimetic strategy to synthesize hydroxyapatite (HAP) inside of crosslinked gelatin nanoparticles, which serve as a nanoenvironment for crystal growth in the aqueous phase. The synthesis of gelatin nanoparticles with the inverse miniemulsion technique is very intriguing because of the flexibility offered by the technique in tailoring the properties of the gelatin nanoparticles. It can be shown that the nanoenvironment promotes a different growth environment for the crystal because of the confinement inside the particle. The formation of HAP inside the particles follows Ostwald's rule of stages. At first an amorphous phase is formed, which itself has a great potential to be used as a resorbable bone substitute. This further transforms into single crystalline HAP via an octacalcium phosphate intermediate. The solution‐mediated transformation into the HAP phase without any calcination step is studied in detail using transmission electron microscopy (TEM) and X‐ray diffraction (XRD) measurements.     

基于MEGA2560的低成本飞控系统双存储方案的设计

针对某型航拍无人机不同任务阶段对数据存储的速度与容量的不同性能要求,设计了高速Flash加大容量SD卡的双存储数据记录模块。实现了对飞行器姿态、GPS以及控制指令等信息的完整记录,系统经试飞验证效果良好。该系统可作为黑匣用于故障分析,又可用于后期航拍图像处理以及控制策略优化、航拍轨迹优化分析,对于野外航拍任务数据记录具有重要的实用价值。     

未来数据储存技术与硬盘的发展

走过了半个世纪的磁储存技术,小型化牵动着数据储存和计算机硬盘到达了从未有过的高度。正在研究发展的热辅助记录技术和图形媒介技术将会给磁记录硬盘带来更高的面密度,从而使小型化在磁储存的框架内还将有一段路可走。但由于其物理限制,磁硬盘无法永远继续小下去,人们正在寻找新的出路。因此除了对磁储存正在发展的两项新技术之外,特别是对完全另辟新路的非磁数据储存技术,如纳米机械AFM数据储存技术、全息光储存技术以及原子储存技术进行了论述,以显示当前该领域前沿科技的发展概貌。     

Magnetic (Hyper)Thermia or Photothermia? Progressive Comparison of Iron Oxide and Gold Nanoparticles Heating in Water,in Cells,and In Vivo

Magnetic hyperthermia (MHT) and photothermal therapy (PTT) are emergent state‐of‐the‐art modalities for thermal treatment of cancer. While their mechanisms of action have distinct physical bases, both approaches rely on nanoparticle‐mediated remote onset of thermotherapy. Yet, are the two heating techniques interchangeable? Here, the heating obtained either with MHT or with PTT is compared. The heating is assessed in distinct environments and involves a set of nanomaterials differing in shape (spheres, cubes, stars, shells, and rods) as well as in composition (maghemite, magnetite, cobalt ferrite, and gold). The nanoparticle's heating efficacy in an aqueous medium is first evaluated. Subsequently, the heating efficiency within the cellular environment, where intracellular processing markedly decreases MHT, is compared. Conversely, endosomal sequestration could have a positive effect on PTT. Finally, iron oxide nanocubes and gold nanostars are compared in MHT and PTT in vivo within the heterogeneous intratumoral environment. Overall, two distinct therapeutic approaches, related to high dosage allowing MHT and low dosage associated with PTT, are identified. It is also demonstrated that PTT mediated by magnetic nanoparticles has an efficacy that is comparable to that of plasmonic nanoparticles, but only at significant nanoparticle dosages. At low concentrations, only plasmonic nanoparticles can deliver a therapeutic heating.