Smart Surface of Gold Nanoparticles Fabricated by Combination of RAFT and Click Chemistry

A simple efficient post‐modification route to the fabrication of hybrid gold nanoparticles with poly(N‐isopropylacrylamide) (PNIPAm) based on click chemistry is described. The PNIPAm was prepared by reversible addition fragmentation chain transfer radical polymerization (RAFT). The PNIPAm was immobilized onto gold nanoparticles with grafting densities of 5.8 chains · nm⁻² by a click reaction. The hybrid gold nanoparticles showed a temperature responsive phenomenon as the temperature changed between 20 and 45 °C.

     

巧用智能手机测定抗贫血药物中铁的含量

铁离子和硫氰化钾反应生成稳定的血红色络合物硫氰化铁,用智能手机拍摄所得图像的颜色反映在图像的RGB值上。随着该溶液浓度的增大,溶液颜色逐渐加深,反映在拍摄的图像中颜色的RGB值也在变化,并且得出该溶液颜色的R值与溶液的浓度成线性关系。结果显示,用该实验方法测得的抗贫血药物中铁的含量与用紫外分光光度法测得同一药品中铁的含量相比误差为5%;并且该实验方法在中学的化学实验课中很容易实现,避免了学生用目视比色法测量抗贫血药物中铁的含量时因标准溶液的色阶选择不合适而导致实验的失败。     

Nanocomposite smart hydrogels with improved responsiveness and mechanical properties: A mini review

Responsive hydrogels have the ability to change their volume, transparency, or other properties in response to external chemical and/or physical stimuli. The responsiveness properties including responsive rate and degree, as well as mechanical properties such as Young's modulus, toughness, breaking strength, and breaking strain are crucial parameters of the smart hydrogels that determine the scope of hydrogel applications such as soft actuators, artificial muscles, and tissue engineering scaffolds. In this paper, the development of the nanocomposite smart hydrogels, which can achieve both improved responsiveness and mechanical properties, is reviewed. First, the fabrication approaches for building the nanocomposite networks by doping organic or inorganic nanomaterials via crosslinking or blending strategies are introduced. Then, the mechanisms used to improve both responsiveness and mechanical properties of nanocomposite responsive hydrogels are discussed. Finally, the perspectives as well as current challenges of such nanocomposite responsive hydrogels are addressed. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018 , 56, 1306–1313     

Ensuring Quality of Experience in the Connected Home: A New Battleground for Quality of Experience Differentiation

ABSTRACT

The connected home is a critical part of the network—but one that has seen little in the way of true investment in recent years. With customer loyalty and churn directly linked to quality of experience, this is a part of the network that no players in the supply chain can afford to ignore any longer. Beyond broadband experience, the addition of smart technology to the connected home also represents one of the biggest revenue growth areas in the consumer telecoms market for some time. From both a churn-reduction and a revenue-growth perspective, investment in the connected home network must accelerate. This article outlines the key trends identified by Ovum in the connected home space for 2016 and beyond.     

基于贝叶斯的智能电能表可靠性评估方法

针对具有高可靠、长寿命特点的智能电能表,应用加速退化试验方法进行可靠性评估是一种有效的方法。开展加速退化试验过程中,在高加速应力激发下,一方面可观测到智能电能表的性能退化,也可能出现智能电能表的整表失效。如何融合智能电能表加速寿命试验过程中的整表失效数据、性能退化数据转化得到的伪寿命数据,从而进行智能电能表的综合可靠性评估,是智能电能表可靠性评估急需解决的问题。本文研究提出基于贝叶斯方法的智能电能表可靠性评估方法,给出融合智能电能表的整表失效数据、伪寿命数据的数据处理方法及计算模型,探讨了伪失效数据计算方法、整表失效数据与伪失效寿命数据相容性检验方法等。     

含ER流体板结构的振动特性研究

本文制作了含电流变体夹层梁和模拟飞机蒙皮结构的含电流变体加筋层合板,采用响应幅频法,测试了在不同电场强度梁和层合加筋板结构各阶固有频率和振幅的变化;并着重测试了加筋层合板结构在改变板材料、电流变体作用面积等条件时各阶频响特性的变化。实验结果表明,随着电场强度的增加,夹层梁的频响特性有很大变化;而层合板的固有频率变化不大,但振幅却有显著变化,其中铝－层合加筋板的频响幅值的变化率达到５０．１％。     

Smart nanocomposite polymer gels

The combination of polymers with nanomaterials displays novel and often enhanced properties compared to the traditional materials. They can open up possibilities for new technological applications. The magnetic polymer gel represents a new type of composites consisting of small magnetic particles, usually from the nanometer range to the micron range, dispersed in a highly elastic polymeric gel matrix. Combination of magnetic and elastic properties leads to a number of striking phenomena that are exhibited in response to impressed magnetic fields. Giant deformational effects, high elasticity, anisotropic properties, temporary reinforcement and quick response to magnetic field open new opportunities for using such materials for various applications.     

Self-Assembled Multistable Scattering Mode for Versatile Energy-Saving Smart Windows

Smart windows are crucial to dynamic control over light transmission to fulfill various demands in energy saving, privacy, and information display; however, most present technologies still perform a single function (often tint or haze adjustment) and require continuous electricity for operation. In this study, novel self-assembled ionic liquid crystals (ILCs) doped with negative cholesteric liquid crystals (CLCs) to offer electrically switchable and stable scattering-mode light modulators are presented. The novel smectic A phase based on the ILCs exhibits high solubility in the adopted nematics, enhancing the LC device's performance in several ways, including improved homogeneity, stable alignment quality, prolonged stability, and simplified fabrication. The LC device can potentially offer a dynamically rapid switching function between stable transparent (imperfect fingerprint textures) states and stable scattering (focal conic textures with small domains) states by using external stimuli and highly maintained multistable states for prolonged periods, even when the external stimuli are removed. The LC device also offers polarization-independent scattering and transparent-mode LC light modulators, low operating voltage, excellent contrast, and broad viewing angles. Its versatility and outstanding field-off stability make it ideal for various applications such as smart lighting, building climate control, energy-saving displays, and augmented reality (AR) glasses.     

Synthesis and characterization of reversible thermosensitive methylated chitin and its application in zinc-ion battery thermal runaway

Novel water-soluble methylated chitins (MCHs) were synthesized homogeneously in aqueous alkaline solution. The relatively mild reaction conditions resulted in the MCH with high degree of acetylation (DA >0.76). The chemical structure of the obtained MCHs was analyzed and the degree of methylation substitution (DS) and DA were determined by proton NMR in both D₂O and 20% DCl/D₂O. The MCH aqueous solutions (DS = 0.46 ~ 0.71) showed a reversible thermosensitive sol–gel–sol transition upon heating and cooling. The gel transition temperature of these MCHs (in the range of 15–85 °C) increased with increasing DS and decreasing polymer concentration. Thermal runaway has been an important safety issue impeding the development of high-energy-density zinc-ion batteries. A smart thermosensitive reversible electrolyte was prepared based on this MCH for the aqueous zinc-ion battery to prevent thermal runaway. When the temperature of zinc-ion battery rises or even gets out of control, the thermosensitive electrolyte can quickly gel and inhibit the migration of zinc ions, resulting in increase of the internal resistance and realizing intelligent and efficient thermal self-protection. Thus the novel thermosensitive methylated chitin shows promise for safe aqueous zinc-ion batteries.