Swarming Microdroplets to a Dexterous Micromanipulator

Many astonishing biological collective behaviors exist in nature, and artificial microrobotic swarms have been developed by emulating these scenarios. However, these microswarms typically have single structures and lack the adaptability that many biological swarms exhibit to thrive in complex environments. Inspired by viscoelastic fire ant aggregations and using a combination of experiment and simulation, a strategy to trigger ferrofluid droplets into forming microswarms exhibiting both liquid-like and solid-like behaviors is reported. By spatiotemporally programming an applied magnetic field, microswarms can be liquefied to implement reversible elongation with a high aspect ratio and solidified into entireties to perform overturning and bending behaviors. It is demonstrated that reconfigurability enables the microswarm to be a mobile dexterous micromanipulator, acting not only as a soft “octopus arm” to explore a confined environment and grasp a targeted object but also adaptively navigate multiple terrains, such as uneven surfaces, curved grooves, complex mazes, high steps, narrow channels, and even wide gaps. This microrobotic swarm can reconfigure both shapes and tasks based on the demands of the environment, presenting novel solutions for a variety of applications.     

In-line characterization of dispersion uniformity evolution during a twin-screw blending extrusion based on near-infrared spectroscopy

Properties of an immiscible polymer blend have been proved to be closely related to dispersion uniformity of the minor phase. At present, dispersion uniformity is difficult to evaluate during the blending process, resulting in hysteretic feedback. Aiming at this problem, this work utilized near-infrared (NIR) spectroscopy to in-line characterize dispersion uniformity evolution during a twin-screw extrusion. A multichannel NIR measurement system was set up and applied to evaluate the blending process of polypropylene and polyolefin elastomer (POE). Based on the NIR spectra collected at different positions of the extruder, five prediction models of POE content were established using the light gradient boosting machine algorithm. Dispersion uniformity was characterized through the fluctuation of the predicted content. The evolution of dispersion under such processing parameters was consistent with scanning electron microscopy.     

Tuning Parameter Selection Based on Blocked $$3\times 2$$3×2 Cross-Validation for High-Dimensional Linear Regression Model

Neural Processing Letters - In high-dimensional linear regression, selecting an appropriate tuning parameter is essential for the penalized linear models. From the perspective of the expected...     

Preparation of tunable full-color emission carbon dots and their optical applications in ions detection and bio-imaging

In this work, we synthesized a series of novel carbon dots (CDs) by using phenylenediamines (three isomers: o-phenylenediamine, m-phenylenediamine, and p-phenylenediamine) as starting materials via facile solvothermal approach. As-prepared CDs could emit bright blue, green, yellow, orange, and red light with relatively high PLQY, individually. Optical properties could be controlled by simply varying reaction parameters. The luminescent mechanism was investigated and analyzed in detail. Finally, the blue-emitting CDs and green-emitting CDs showed many appealing properties, such as high sensitivity (limit of detection = 4.52 and 3.50 nmol/L), quick response (<2 minutes), broad response window (0-70 nmol/L), and excellent selectivity for detecting Cr⁶⁺ and Al³⁺ cations, respectively. Thus, they have potential to be developed as the corresponding optical probes. While as-prepared orange-emitting CDs could be applied as a bio-imaging reagent due to its long-wavelength emission, relatively high PLQY, low toxicity, excellent water solubility, and good biocompatibility.     

Ultralight and robustly compressible silica aerogel enhanced by AC/C sponge with high oil/water separation

Journal of Porous Materials - In recent years, oil spills and industrial organic pollutants have caused irreparable damage to the environment and biological ecosystems. Therefore, the treatment of...     

四川省植被覆盖时空演变及未来变化趋势分析

四川省地处长江上游,是长江流域重要的生态屏障;解析该区域植被覆盖的时空演变特征,对长江上游的生态环境修护与治理具有重要意义。基于长时间序列的MODIS NDVI数据,解析2000~2016年间四川省植被的空间分布格局与时间变化特征;采用趋势分析法和Hurst指数,预测未来植被的变化趋势及持续性。结果表明:(1)四川省NDVI多年平均值为0.50,植被覆盖整体上呈现川东高于川西的空间分布特征;(2)2000~2016年间,四川省的NDVI值在0.48至0.53之间波动,整体呈上升趋势,增长率为0.002 5/a;(3)植被覆盖度在未来变化将呈现改善大于退化的趋势;植被持续性改善的面积大于持续性退化的面积。     

固体火箭包覆层脱粘调制红外热波检测法的数值模拟

调制红外热波无损检测是一种可以检测材料内部缺陷的先进技术,在固体火箭发动机包覆层脱粘的诊断中有一定的应用前景.以有限元法对固体火箭发动机包覆层脱粘的调制红外热波检测法进行数值模拟,研究加热条件和结构对可检测性的影响.得出可检信息参数(表面过余温度幅值、相位和相位差)随热波激励条件(调制频率、热流强度)和结构参数(材料、...     

多模式匹配算法研究和优化

模式匹配在网络安全领域有着重要的应用,随着网络环境的日益复杂,模式集合也随之增加.如何高效处理千万模式集下的字符串匹配成为网络安全的瓶颈之一.本文针对多模式匹配算法AC算法和WM算法进行了研究,采用了新型基于层次扫描和子节点数目搜索的双数组AC算法;从hash函数的选取和模式串的Tree树存储对WM算法进行了优化.能有效减少系统的内存占用,提高匹配效率.     

Ionic Modulation of Interfacial Magnetism in Light Metal/Ferromagnetic Insulator Layered Nanostructures

Ferromagnetic insulator thin film nanostructures are becoming the key component of the state‐of‐the‐art spintronic devices, for instance, yttrium iron garnet (YIG) with low damping, high Curie temperature, and high resistivity is explored into many spin–orbit interactions related spintronic devices. Voltage modulation of YIG, with great practical/theoretical significance, thus can be widely applied in various YIG‐based spintronics effects. Nevertheless, to manipulate ferromagnetism of YIG through electric field (E‐field), instead of current, in an energy efficient manner is essentially challenging. Here, a YIG/Cu/Pt layered nanostructure with a weak spin–orbit coupling interaction is fabricated, and then the interfacial magnetism of the Cu and YIG is modified via ionic liquid gating method significantly. A record‐high E‐field‐induced ferromagnetic resonance field shift of 1400 Oe is achieved in YIG (17 nm)/Cu (5 nm)/Pt (3 nm)/ionic liquid/Au capacitor layered nanostructures with a small voltage bias of 4.5 V. The giant magnetoelectric tunability comes from voltage‐induced extra ferromagnetic ordering in Cu layer, confirmed by the first‐principle calculation. This E‐field modulation of interfacial magnetism between light metal and magnetic isolator may open a door toward compact, high‐performance, and energy‐efficient spintronic devices.