A Facile Approach toward Thermoplastic Triple-Shape Memory Polymers

In this work, a ternary blend of polyolefin elastomer (POE), lauric acid (LA), and poly(ε-caprolactone) (PCL) with triple-shape memory effect (triple-SME) is reported. LA and PCL exhibit distinct thermal transitions and construct two reversible switching networks capable of fixing and releasing different temporary shapes under a mild condition. The ternary blend shows excellent triple-shape memory properties and good toughness. Besides, the permanent shape can be reconfigured by a simple thermal treatment. These particular features make the novel blend a competitive candidate for diverse applications. And the creative combination of crystalline small molecule and semicrystalline polymer expands the freedom for producing triple-shape memory polymers (triple-SMPs).     

Effects of micro-sized mullite on cristobalite crystallization and properties of silica-based ceramic cores

Silica-based ceramic cores are extensively used in investment casting process, during which they must exhibit sufficient flexural strength and deformation resistance. In this study, micro-sized mullite was used as an additive to silica-based ceramic cores to optimize their high temperature properties. To investigate the effects of micro-sized mullite on cristobalite crystallization, mechanical and thermal properties of silica-based ceramic cores, ceramic cores with different amounts of micro-sized mullite were fabricated. The XRD results showed that additional micro-sized mullite diminished the crystallization of cristobalite at high temperatures, primarily caused by the mullite related compressive stresses on the surface regions of fused silica particles. Three-point bending tests and SEM results showed that micro-sized mullite had a more significant effect on the flexural strength of ceramic cores compared with conventional additives. Particularly, the fracture mechanism of silica-based ceramic cores had been changed from intergranular fracture into a mixed fracture consisting of both intergranular and transgranular fracture. The mechanical and thermal properties of ceramic cores were all reduced slightly as the mullite content exceed 4.6 wt%. Hence, to optimize the properties of silica-based ceramic cores, the micro-sized mullite content should not exceed 4.6 wt%.     

Correction to: Bismuth Yttrium Oxide (Bi3YO6), A New Electrode Material For Asymmetric Aqueous Supercapacitors

Journal of Inorganic and Organometallic Polymers and Materials - The original version of this article unfortunately contained mistakes. In line 9 of the abstract, 5% should read as 2%. The...     

冷却机固定篦床处的衬砌设计

篦冷机是烧成系统中重要的组成设备之一,其性能不仅会影响二、三次风温的高低及余热发电取风的温度,而且影响出冷却机熟料的温度,甚至会影响熟料的质量及后续的水泥粉磨。国内外篦冷机研发公司,对篦冷机的结构设计与性能挖掘已经十分深入,特别是对入料端的设计,已经基本上达成共识,形成了一致的倾斜式固定篦床的设计。由于篦冷机入料口接收来自回转窑的1 300 ℃以上的高温熟料,作为一个换热回收的主要设备,其固定篦床处的衬砌结构与样式,也会在一定程度上影响篦冷机的使用性能。为了更好地发挥冷却机的工艺性能,对篦冷机固定篦床处的衬砌设计作一探讨。     

二阶高通滤波器的计算及设计

滤波装置分一阶、二阶、高通及C型四种。高通滤波器主要滤13以上谐波。该装置对某次频率以上呈现低阻抗。本文从高通滤波器的原理出发，对其参数进行分析与推导，并举了实例。     

工艺参数对微区沉淀法制备纳米MgAl2O4粉体的影响

采用高分子网络微区沉淀法制备纳米镁铝尖晶石（MgAl2O4）粉体，并采用TGA／DTA、XRD和TEM等分析测试技术对前驱体的热分解和所制得粉体的物相组成、形貌及颗粒尺寸进行表征，结果表明所制得的MgAl2O4粉体颗粒粒径小，结晶良好，成分单一且粒径大小均匀。而实验过程中工艺参数的改变会对生成粉体的粒径和形貌产生一定的影响，进而即研究了各种工艺参数的改变对该方法制备纳米MgAl2O4粉体的影响。     

THEORETICAL INVESTIGATION ON BY-ONLY-CURRENT ELECTROMAGNETIC SEPARATION OF INCLUSION FROM MOLTEN METALS

The electromagnetic field under applied AC and DC current in round and rectangular pipe was systematically investigated, then a concept of "equivalent current density" was proposed for evaluating the inhomogeneous electromagnetic pinch force, and the mono-component removal efficiency and the overall removal efficiency of inclusion were formulated. It is founded that flat pipe is superior to round pipe for the electromagnetic removal of inclusion, and DC current can get a higher removal efficiency than A C current due to absence of skin phenomenon. Under usual condition, a removal efficiency of 52% for 10μm inclusion or more than 92% for 20μm inclusion can be achieved by imposing a current density of 3×106A/m2 in a flat pipe.     

氧化剂对Cu-Al2O3复合材料微观组织的影响

研究了一种新型简化内氧化工艺,并制备了不同氧源系数的Cu-Al2O3复合材料。用SEM、TEM等分析手段对所制备复合材料烧结态的微观组织进行了研究。结果表明,该简化工艺成功制备了Cu-Al2O3复合材料,在铜基体上弥散分布着大量细小的γ-Al2O3颗粒,其粒径为5~20nm,颗粒间距为25~60nm,当氧源系数(k)为1.20时,压制粉末经烧结(950℃,4h)后全部完成内氧化,此氧化剂含量为最佳的内氧化氧化剂添加量。     

快淬工艺对无钴AB5型贮氢合金循环稳定性的影响

研究了快淬工艺对无钴AB5型LaxMm1-x(NiMnSiAlFe)4.9(x=0,0.45,0.75,1.0)合金微观结构及电化学循环稳定性的影响.结果表明快淬处理显著改善合金的成分均匀性,使晶粒细化,并显著提高合金的循环稳定性.当淬速从0m/s增加到28 m/s时,经300次充放循环后,x=0.45合金的容量衰减率D从0.28 mAh/g·c-1(c代表一次循环)下降到0.13mAh/g·c-1;x=1.0合金的容量衰减率D从0.3mAh/g·c-1下降到0.14mAh/g·c-1.