3D Printed Stem‐Cell Derived Neural Progenitors Generate Spinal Cord Scaffolds

A bioengineered spinal cord is fabricated via extrusion‐based multimaterial 3D bioprinting, in which clusters of induced pluripotent stem cell (iPSC)‐derived spinal neuronal progenitor cells (sNPCs) and oligodendrocyte progenitor cells (OPCs) are placed in precise positions within 3D printed biocompatible scaffolds during assembly. The location of a cluster of cells, of a single type or multiple types, is controlled using a point‐dispensing printing method with a 200 µm center‐to‐center spacing within 150 µm wide channels. The bioprinted sNPCs differentiate and extend axons throughout microscale scaffold channels, and the activity of these neuronal networks is confirmed by physiological spontaneous calcium flux studies. Successful bioprinting of OPCs in combination with sNPCs demonstrates a multicellular neural tissue engineering approach, where the ability to direct the patterning and combination of transplanted neuronal and glial cells can be beneficial in rebuilding functional axonal connections across areas of central nervous system (CNS) tissue damage. This platform can be used to prepare novel biomimetic, hydrogel‐based scaffolds modeling complex CNS tissue architecture in vitro and harnessed to develop new clinical approaches to treat neurological diseases, including spinal cord injury.     

Preparation and properties of pure crystalline perovskite CeFeO3 thin films with vanadium doping

Cerium ferrite (CeFeO₃) thin films doped with vanadium (V:CeFeO₃) were grown on SiO₂ quartz glass and <100>‐oriented SrTiO₃ (STO) crystal substrates by the radio‐frequency magnetron sputtering method in this study. The effects of crystallization, substrate, and V‐doping on the quality, the magnetic property and the magneto‐optical property of as‐prepared films are investigated. V:CeFeO₃ film grown on STO substrate has better crystallinity and has better lattice integrity due to the higher lattice matching between substrate and film. The magnetic hysteresis loop and the magnetic circular dichroism spectra show that the magnetization strength and the magneto‐optical properties of V:CeFeO₃ films have the significant anisotropy. Moreover, V‐doping and the stress lead to the change in easy magnetization direction of film. It shows that the perovskite B‐site doping with transition‐metal ion has significant influence on the magnetic and the magneto‐optical properties of CeFeO₃ thin films.     

Flow properties of polymer melt in longitudinal ultrasonic‐assisted microinjection molding

Microplastic parts are usually fabricated by microinjection molding (µIM) which is an effective and low cost method. But the defects, such as short shot, often appear during fabricating plastic parts with high aspect ratio structures or complex shapes. a longitudinal ultrasonic‐assisted microinjection molding (LUµIM) method effectively improve the molding quality. In the paper, the mechanism that the ultrasonic vibration impacts on the polymer melt is investigated. Considering from the point view of energy effect, mechanical energy transmission, and mechanical energy conversion, which are divided from the energy of ultrasonic vibration, are analyzed. The model of energy transmission and a new rheological equation including the parameters of ultrasonic vibration are established to describe the rheological behavior of polymer melt in microcavity. The simulation results show that the ultrasonic vibration improves the viscosity field and the velocity field in complex shaped microcavity, and leads to a better filling capability and uniformity of the polymer melt. This research achievement can be used to guide the process flow and parameter selection of LUµIM. POLYM. ENG. SCI., 57:797–805, 2017. © 2016 Society of Plastics Engineers     

中小企业内部网络构建的研究

随着信息时代的到来,计算机和通信在信息的传输、收集、存储、处理和分发中扮演了极其重要的角色,故而,中小企业内部的网络建设已经成为提升中小企业核心竞争力的关键因素.     

气象自动站采集器结构及维护

随着气象事业发展,气象自动站不断更新换代,气象自动站采集器型号、功能、配置也不断更改。为更好保障气象装备正常运行,文章对常用气象自动站采集器的结构原理及维修维护方法进行了调查研究。     

福建沿海某区域10kV架空绝缘导线失效分析

通过宏观拍照、傅立叶变换红外光谱(FTIR)、热重(TG)分析和扫描电子显微镜(SEM)等方法详细分析了福建省沿海某区域雷击烧蚀的部分失效样品,使用有限元分析方法分析了绝缘子负荷侧的受力情况。结果表明,失效样品主要表现出断链,氧化老化较少。炭黑量过多会使绝缘层过早失效。绝缘子负荷侧存在最大的应力和应力变形,使得设计上"先天不足"架空绝缘导线在电弧电流产生的堆积热量和应力作用下力学性能降低,产生大量裂纹。绝缘材料本身避免"绝缘薄弱处"是从根本上真正提高架空绝缘导线寿命的关键。     

臭氧催化氧化法对尾矿淋溶液中氨氮的去除研究

采用臭氧-载铜活性炭催化氧化法处理黄金尾矿闭库淋溶液,探讨了活性炭在臭氧氧化过程中的作用机理及p H对臭氧催化氧化降解氨氮的影响。试验结果表明:催化剂的投加显著提高了氨氮的去除率。初始p H为9.57时,O3氧化对氨氮的去除率仅为54.38%,而投加活性炭和载铜活性炭后,氨氮的去除率分别提高到63.92%和70.67%;随着废水的初始p H由7.2增加到11.43,氨氮的去除率由28.35%增加到99.45%。     

煤化工废水处理技术研究与进展

介绍了煤化工废水的来源、水质特点和处理难题。针对煤化工废水主要处理技术,即分离技术、生物技术和高级氧化技术,综述了国内外有关研究的现状、发展趋势和应用。展望了未来的研究方向,指出各种处理技术的组合和优化,缓解废水对生物工艺的毒性抑制性,达到高效生物脱氮的效果,是实现煤化工废水"零排放"的必然趋势。     

Novel Direct Nanopatterning Approach to Fabricate Periodically Nanostructured Perovskite for Optoelectronic Applications

While indirectly patterned organic–inorganic hybrid perovskite nanostructures have been extensively studied for use in perovskite optoelectronic devices, it is still challenging to directly pattern perovskite thin films because perovskite is very sensitive to polar solvents and high‐temperature environments. Here, a simple and low‐cost approach is proposed to directly pattern perovskite solid‐state films into periodic nanostructures. The approach is basically perovskite recrystallization through phase transformation with the presence of a periodic mold on an as‐prepared solid‐state perovskite film. Interestingly, this study simultaneously achieves not only periodically patterned perovskite nanostructures but also better crystallized perovskites and improved optical properties, as compared to its thin film counterpart. The improved optical properties can be attributed to the light extraction and increased spontaneous emission rate of perovskite gratings. By fabricating light‐emitting diodes using the periodic perovskite nanostructure as the emission layers, approximately twofold higher radiance and lower threshold than the reference planar devices are achieved. This work opens up a new and simple way to fabricate highly crystalline and large‐area perovskite periodic nanostructures for low‐cost production of high‐performance optoelectronic devices.