High-gravity-assisted green synthesis of rare-earth doped calcium molybdate colloidal nanophosphors

In this work, we report an innovative route for the synthesis of rare-earth doped calcium molybdate (CaMoO₄) nanophosphors by using high gravity rotating packed bed (RPB) technology and paraffin liquid as the solvent. The significant intensified mass transfer and micromixing of reactants in the RPB reactor are benefiting for homogeneous doping of rare-earth ions in the host materials, leading to nanophosphors with high quantum efficiency. The use of liquid paraffin as the solvent eliminates the safety risks associated with volatile organic compounds, increasing the potential for clean production of nanophosphors. Under excitation of deep ultraviolet (DUV) light, the CaMoO₄:Na⁺, Eu³⁺ nanophosphors exhibit red emission at peak wavelength of 615 nm and quantum yield of up to 35.01%. The CaMoO₄:Na⁺,Tb³⁺ nanophosphors exhibit green emission at peak wavelength of 543 nm with quantum yield of up to 30.66%. The morphologies of the nanophosphors are tunable from nanofibers through nanorods to nanodots and the possible mechanism of controlling the formation of different nanostructures is proposed on the basis of experimental results and theoretical analysis of mesoscience. These nanophosphors are highly dispersible in organic solvents and utilized for fabricating fabrication of flexible, freestanding luminescent films based on silicone resin. We also demonstrate the red LEDs consisting of the hybrid films of CaMoO₄:Na⁺,Eu³⁺ nanoparticles as color-converting phosphors and DUV LEDs as illuminators, offering strong potential for future nanophosphors-basedsolid-state lighting systems.     

The Fifth WS/DGAT Enzyme of the Bacterium Marinobacter aquaeolei VT8

Wax esters (WE) belong to the class of neutral lipids. They are formed by an esterification of a fatty alcohol and an activated fatty acid. Dependent on the chain length and desaturation degree of the fatty acid and the fatty alcohol moiety, WE can have diverse physicochemical properties. WE derived from monounsaturated long-chain acyl moieties are of industrial interest due to their very good lubrication properties. Whereas WE were obtained in the past from spermaceti organs of the sperm whale, industrial WE are nowadays mostly produced chemically from fossil fuels. In order to produce WE more sustainably, attempts to produce industrial WE in transgenic plants are steadily increasing. To achieve this, different combinations of WE producing enzymes are expressed in developing Arabidopsis thaliana or Camelina sativa seeds. Here we report the identification and characterization of a fifth wax synthase from the organism Marinobacter aquaeolei VT8, MaWSD5. It belongs to the class of bifunctional wax synthase/acyl-CoA:diacylglycerol O-acyltransferases (WSD). The protein was purified to homogeneity. In vivo and in vitro substrate analyses revealed that MaWSD5 is able to synthesize WE but no triacylglycerols. The protein produces WE from saturated and monounsaturated mid- and long-chain substrates. Arabidopsis thaliana seeds expressing a fatty acid reductase from Marinobacter aquaeolei VT8 and MaWSD5 produce WE. Main WE synthesized are 20:1/18:1 and 20:1/20:1. This makes MaWSD5 a suitable candidate for industrial WE production in planta.     

氧化石墨烯杂化分子印迹复合膜制备及性能研究

采用改进的Hummers法,通过冷冻干燥制备了氧化石墨烯(GO)。以辛弗林盐酸盐为模板分子,水溶性的丙烯酰胺为功能单体,离子液体(溴代1-丁基-3-甲基咪唑)为致孔剂,把GO加入聚合液中,制备了GO杂化的分子印迹复合膜(GO-MIM)。利用透射电镜、扫描电镜、X射线衍射和红外光谱等方法对GO及GO-MIM进行了表征。通过将分子印迹膜技术与GO相结合,明显提高了分子印迹膜的力学性能。吸附及渗透实验表明,GO-MIM可在纯水溶剂体系,对辛弗林盐酸盐具有很好的选择性吸附能力和优先透过能力,体现了明显的分子印迹效果。     

Micro/nanocellular polyprolene/trans-1,4-polyisomprene (PP/TPI) blend foams by using supercritical nitrogen as blowing agent

Toughed polypropylene (PP) foams, with the combination of blending with trans-1,4-polyisoprene (TPI) and micro/nanocellular structure in the matrix, were prepared using a batch foaming process and N₂ as the blowing agent. The incorporation of TPI in the PP matrix induces the enhanced formability and the slightly improved ductility and toughness compared to the neat PP. The simultaneous existence of the TPI phase and micro/nanocellular structure makes the fracture behavior follow the shear yielding of a bundle of fibrils in the tensile load direction. The results of mechanical properties measurements show that the notched Izod impact strengths of foamed PP/TPI blend are two to three times larger than those of the unfoamed counterparts. The PP/TPI blend foam with 5phr TPI content shows the highest impact strength when the foaming temperature is 140°C, which is fivefold increase over that of the neat PP. The enhanced ductility and toughness of PP/TPI foams were found with the increasing foaming temperature. The insert of micro−/nanocellular in PP/TPI blends simultaneously makes the notched impact strength increase significantly, tensile strength decrease, and elongation at break increase obviously, which provides the possibility to combine the higher impact strength and toughness with the advantage of microcellular foaming. POLYM. ENG. SCI., 60:211–217, 2020. © 2019 Society of Plastics Engineers     

采场结构参数与放矿方式的相似物理试验优化研究

基于单漏斗放矿试验,对放出椭球体形态发展趋势进行了分析,确定最终放出椭球体轴偏角、偏心率等核心指标。基于立体放矿模型,对比无贫化与低贫化两种放矿方式下回贫差指标,对放矿方式进行了优选。在物理试验结果基础上,采用相似物理试验法、经验类比法、理论分析法相结合的方法,对大间距椭球体排列形式下的采场结构参数进行优化,确定20m分段高度下的进路间距、崩矿步距、放矿步距、放矿方式等关键参数与工艺。采场结构参数优化的过程与结果,可以为同类工艺矿山参数设计提供技术参考。     

滚球半径法确定瓦斯抽放泵站放空管合理安置区域

为了确定瓦斯抽放泵站放空管合理安置区域。在滚球半径法推算原理的基础上,利用几何知识,使用AutoCAD绘图软件绘制瓦斯抽放泵站放空管合理安置区域,而非传统方法的若干公式计算。AutoCAD绘图软件作图的方法避免了《GB 50057-2010建筑物防雷设计规范》附录D中传统方法繁琐的计算。确定瓦斯抽放泵站放空管合理安置区域作图法直观、简单、清晰、明了,简化了瓦斯抽放泵站防雷设计工作。为科学合理确定瓦斯抽放泵站放空管位置提供了依据。     

岩巷快速施工技术在宏阳煤矿的应用研究

为了提高岩巷的施工速度,宏阳煤矿采取更换施工设备、改进施工工艺等措施,使施工速度由每月80m提高至每月160m。总结出一套适合本矿的岩巷快速施工技术。     

活化CO2气体保护焊的研究

详细研究了自制的活性焊丝对CO2气体保护焊的影响.结果表明,使用活性剂可以使焊接飞溅率大大降低,焊缝熔深增加,熔宽增大,深宽比增加,熔滴以细颗粒过渡.分析认为CO2气体保护焊飞溅降低的原因,是因为活性剂的加入在降低了混合气体有效电离电压的同时显著增加了CO2电弧的导电能力,使电弧能量密度增加,从而使中等电流下的熔滴过渡方式由大颗粒过渡转变成细颗粒过渡;焊缝成型的变化是电弧收缩与表面张力变化双重作用的结果.     

基于马尔可夫状态转移的变压器剩余寿命预测

提出了一种基于马尔可夫状态转移矩阵的变压器缺陷转移率预测方法。利用变压器历史缺陷记录,建立威布尔分布模型拟合得到变压器缺陷转移率,将其应用于马尔可夫状态转移矩阵中,得到变压器不同状态之间的转移率,并引入了回退因子进行修正;基于该缺陷转移率,通过构建比例故障模型对变压器剩余寿命进行预测,结果表明,所提方法预测出的剩余寿命价值更加贴合变压器实际运行状况,验证了其合理性和可靠性。