Melting process and melt structure of fly ash/magnesium slag blends for the production of inorganic fibers

Fiber production from inorganic industrial solid wastes is an effective waste management strategy. Because of cost considerations, most enterprises generally use local solid wastes as raw materials to produce fibers. In this study, we explored the feasibility of producing fibers using fly ash and magnesium slag. The results show that the melting temperature of the blends composed of fly ash, magnesium slag, and a small amount of calcined dolomite first decreased and then increased with an increase in acidity coefficient (M_k) from 1.0 to 2.4_. The samples could form a eutectic system in the M_k range of 1.4–1.8, and therefore have a relatively low melting temperature in this M_k range. Fly ash could react with magnesium slag and calcined dolomite to form akermanite, gehlenite-magnesium, and anorthite at temperatures close to the melting temperature; therefore, these crystalline phases were the main reaction products formed in the samples with M_k values lower than 1.80. Anorthite reacted further with some Na-containing and Si-containing spieces to produce labradorite. Thus, the content of anorthite and labradorite rapidly increased and they became the major crystal phases in the blend samples with M_k values greater than 1.80. MAS-NMR spectroscopic analysis revealed that the network structure of the melts depended on the ratio of bridging oxygen to non-bridging oxygen; a high ratio of bridging oxygen to non-bridging oxygen could lead to the formation of a dense network structure in the melt. The blends of fly ash and magnesium slag can be used to produce wool fibers and continuous fibers. In addition, the suitable temperature ranges for the production of both types of fibers were determined. The drawing temperature for continuous fiber production depended on the degree of polymerization and structure of the melt.     

绝对式光电编码器的编码理论研究进展

介绍了用于角度测量的绝对式光电旋转编码器的编码理论研究概况,具体包括反射式格雷码、矩阵码、m序列码和单码道格雷码的绝对位置编码方法和编码特征。绝对位置编码的发展过程是以唯一性和单变性为基础特性,以单码道性为最终目标进行编码矩阵列数的缩减。目前,编码类型的发展经历了n条码道的反射式格雷码、n/3条码道矩阵码、2条码道的m序列码以及1条码道的单码道格雷码,已经达到单码道的最终目标。由于单码道格雷码编码理论尚不完善,仍依赖搜索获得编码,因此其快速构造方法是未来绝对位置编码理论的发展方向。最后,对近几年发展起来的基于图像传感器的非编码测量方法进行了介绍和展望,该方法是对传统测量方法的颠覆,有望成为光电式旋转编码器的另一个发展方向。     

Blends of Bio-Based Poly(Limonene Carbonate) with Commodity Polymers

In this study, blends of the bio-based poly(limonene carbonate) (PLimC) with different commodity polymers are investigated in order to explore the potential of PLimC toward generating more sustainable polymer materials by reducing the amount of petro- or food-based polymers. PLimC is employed as minority component in the blends. Next to the morphology and thermal properties of the blends the impact of PLimC on the mechanical properties of the matrix polymers is studied. The interplay of incompatibility and zero-shear melt viscosity contrast determines the blend morphology, leading for all blends to a dispersed droplet morphology for PLimC. Blends with polymers of similar structure to PLimC (i.e., aliphatic/aromatic polyester) show the best performance with respect to mechanical properties, whereas blends with polystyrene or poly(methyl methacrylate) are too brittle and polyamide 12 blends show very low elongations at break. In blends with Ecoflex (poly(butylene adipate-co-terephthalate)) and Arnitel EM400 (copoly(ether ester)) with poly(butylene terephthalate) hard and polytetrahydrofuran soft segments) a threefold increase in E-modulus can be achieved, while keeping the elongation at break at reasonable high values of ≈200%, making these blends highly interesting for applications.     

Recent advances in carbon nanotubes-based microwave absorbing composites

With the blossom of information industry, electromagnetic wave technology shows increasingly potential in many fields. Nevertheless, the trouble caused by electromagnetic waves has also drawn extensive attention. For instance, electromagnetic pollution can threaten information safety in vital fields and the normal function of delicate electronic devices. Consequently, electromagnetic pollution and interference become an urgent issue that needs to be addressed. Carbon nanotubes (CNTs) have become a potential candidate to deal with these problems due to many advantages, such as high dielectric loss, remarkable thermodynamic stability, and low density. With the appearance of climbing demands, however, the carbon nanotubes combining various composites have shown greater prospects than the single CNTs in microwave absorbing materials. In this short review, recent advances in CNTs-based microwave absorbing materials were comprehensively discussed. Typically, we introduced the electromagnetic wave absorption mechanism of CNTs-based microwave absorbing materials and generalized the development of CNTs-based microwave absorbers, including CNTs-based magnetic metal composites, CNTs-based ferrite composites, and CNTs-based polymer composites. Ultimately, the growing trend and bottleneck of CNTs-based composites for microwave absorption were analyzed to provide some available ideas to more scientific workers.     

Preparation and Evaluation of a Self-Nanoemulsifying Drug Delivery System Loaded with Heparin Phospholipid Complex

A self-nanoemulsifying drug delivery system (SNEDDS) was developed to enhance the absorption of heparin after oral administration, in which heparin was compounded with phospholipids to achieve better fat solubility in the form of heparin-phospholipid (HEP-Pc) complex. HEP-Pc complex was prepared using the solvent evaporation method, which increased the solubility of heparin in n-octanol. The successful preparation of HEP-Pc complex was confirmed by differential scanning calorimetry (DSC), Fourier-transform infrared (FT-IR) spectroscopy, NMR, and SEM. A heparin lipid microemulsion (HEP-LM) was prepared by high-pressure homogenization and characterized. HEP-LM can enhance the absorption of heparin after oral administration, significantly prolong activated partial thromboplastin time (APTT) and thrombin time (TT) in mice, and reduce fibrinogen (FIB) content. All these outcomes indicate that HEP-LM has great potential as an oral heparin formulation.     

浅析钛及钛合金在海洋装备上的应用

钛及钛合金在海洋工程装备领域应用非常广泛，如船体结构件、潜艇和深潜器的耐压壳体、管件、阀及附件、动力驱动装置中的推进器、冷凝器、冷却器、换热器、舰船声呐导流罩、螺旋桨等。本文在介绍钛及钛合金在海洋装备领域应用特点的基础上，总结了目前国内外形成的舰船用钛及钛合金体系和性能特征，分析了国内外钛及钛合金在海洋装备领域的应用现状及优势，展望了钛材在海洋装备的应用前景，以期对后续海洋工程装备设计选材提供参考，从而大幅度加速推动钛材在我国海洋装备领域的应用。     

Effects of Cu on the corrosion behavior and microstructure of Mg–Zn–Ca bulk metallic glass

For the purpose of developing biodegradable magnesium alloys with suitable properties for biomedical applications, Mg–Zn–Ca–Cu metallic glasses were prepared by copper mold injection methods. In the present work, the effect of Cu doping on mechanical properties, corrosion behavior, and glass-forming ability of Mg₆₆Zn₃₀Ca₄ alloy was studied. The experimental findings demonstrated that the incorporation of Cu decreases the corrosion resistance of alloys, but increases the microhardness and degradation rate slightly. However, the addition of a trace amount of Cu can make the samples have antibacterial properties. Therefore, Mg–Zn–Ca–Cu has great advantages in clinical implantation and is the potential implant material.     

煤矿锚杆机除尘马达改进

针对煤矿进口锚杆机除尘马达频繁出现故障的情况,通过排查除尘装置的安装方式和监测马达工作时的压力状态,查找故障原因,并制定解决方案。通过马达外接单向阀,可满足马达进油口最低安全压力限制的要求,解决了马达频繁损坏的问题,保障了设备工作的稳定性,提高了工作效率。