Electrospinning preparation,characterization, and enhanced photocatalytic activity of an Silicotungstic acid (H4SiW12O40)/poly(vinyl alcohol)/poly(methyl methacrylate) composite nanofiber membrane

Silicotungstic acid (H₄SiW₁₂O₄₀)/poly(vinyl alcohol) (PVA)/poly(methyl methacrylate) (PMMA) composite nanofiber membranes were prepared by an electrospinning technique. A PMMA emulsion was mixed with PVA and H₄SiW₁₂O₄₀ evenly in water (electrospinning solvent). The configuration and elemental composition of the membranes were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and X‐ray photoelectron spectroscopy. The results indicate that H₄SiW₁₂O₄₀ with an intact Keggin structure existed in the composite membrane. The as‐prepared H₄SiW₁₂O₄₀/PVA/PMMA membranes exhibited enhanced photocatalytic efficiency (>84%) in the degradation of methyl orange (MO); it outperformed H₄SiW₁₂O₄₀ powder (4.6%) and the H₄SiW₁₂O₄₀/PVA nanofiber membrane (75.2%) under UV irradiation. More importantly, the H₄SiW₁₂O₄₀/PVA/PMMA membranes could be easily separated from the aqueous MO solution, and the photocatalytic efficiency of the membranes decreased inappreciably after three photocatalytic cycles. This may have been due to the enhanced water tolerance of the membranes and the stability of H₄SiW₁₂O₄₀ in the membranes. The photocatalytic process was driven by the reductive pathway with a much faster degradation rate because of the presence of PVA. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43193.     

浅谈浮法玻璃生产线锡槽电加热系统

介绍了锡槽电加热系统以及系统中的关键设备调功器、变压器等,并通过电路分析说明了电加热元件的接线原理及设备安装、调制中需要注意的问题。     

Enhancement of Thermoelectric Performance in Hierarchical Mesoscopic Oxide Composites of Ca3Co4O9 and La0.8Sr0.2CoO3

The natural contradiction in enhancing electrical conductivity and thermopower in thermoelectric oxides makes it hard to improve the performance of a single thermoelectric oxide material. We report a facile method to construct a unique architecture of thermoelectric oxides that is promising to realize a simultaneous improvement of overall electrical conductivity and thermopower. Here, a series of two‐phase nanocomposites comprising of Ca₃Co₄O₉ (CCO) and La_0.8Sr_0.2CoO₃ (LSCO) has been synthesized through ball milling followed by spark plasma sintering (SPS) method. The electron microscope images reveal that the two constituents form the unique composites while retaining their individual crystalline and morphological identities. Owing to the hierarchical mesoscopic structure with nanoscale particles and submicrometer scale grain boundaries, an external strain is induced into the CCO grains by the LSCO nanoparticles to enhance the thermopower. The mesoscopic structure is also favorable for improving the electrical conductivity. Moreover, the long‐wavelength phonons can be scattered effectively from LSCO nanoparticles and the thermal conductivity is further suppressed. With compromises between power factor and thermal conductivity, the largest ZT achieved is up to 0.41 at 1000 K for the composites with 25 wt% of LSCO.     

离心压气机弯管进口畸变非定常特性

采用数值模拟计算的方法研究了90°弯管对涡轮增压器装配的离心压气机进口流场产生的畸变,比较了两种不同轴向位置弯管所致的进口畸变对压气机性能的影响,并对压气机内部的三维非定常流动进行了频域分析.结果表明,弯管畸变对离心压气机性能的恶化程度与弯管所在位置有关,距离叶轮进口较远的弯管影响较大.畸变引起压气机性能在大流量时有明显降低,在小流量时性能恶化程度较小.弯管畸变导致叶轮进口前的压力脉动增强,大流量时改变了叶轮流道上游和叶顶间隙内的压力频谱结构,显著提高了转子基频的扰动强度.同时畸变也造成了叶片振动和蜗壳舌部噪声的恶化,在小流量工况下的作用更加明显.     

生物质水蒸气气化利用过程数学模型的建立

分析了甘蔗渣的水蒸气气化过程,基于气化过程的物料平衡和化学平衡关系,建立了一种生物质气化过程的数学模型。用该模型模拟计算甘蔗渣在水蒸气氛围下气化后的气体成分,计算结果与试验数据基本相符,尤其在温度950℃之后,计算值和测量值更接近。以甘蔗渣和木薯渣为例,研究该气化模型的特性。甘蔗渣和木薯渣水蒸气气化的最佳水蒸气/燃料值(S/B)分别为0.3和0.2。气化气组分和气化效果随温度和S/B变化的结果表明:提高温度有利于气化反应的进行,提高S/B,可以增加气体产率,气体热值有所降低。     

氮原子在钨低指数表面上的吸附和振动

应用原子和表面簇合物相互作用的5参数Morse势法(5-MP)对N-W低指数表面体系进行了研究,并获得了全部临界点特性以及3个面的势能面.计算结果表明:在低覆盖度下,N原子优先吸附在W(100)面的四重洞位H,获得62 meV的垂直振动频率;在W(110)面上只存在三重洞位H3的稳定吸附态,垂直振动频率为43 meV;在W(111)面上最稳定的吸附位为赝式三重位H3,垂直振动频率为79 meV.     

1-苯并噻唑基-3,5-二苯基吡唑啉衍生物的合成与荧光性

设计和合成了7个新型苯并噻唑基-吡唑啉类化合物，通过元素分析和红外光谱检测，确定了化合物的结构，荧光检测结果表明它们的荧光强度为36．1-69.2，荧光强度的大小与衍生物中的取代基有关，溴和甲氧基取代衍生物具有较高的荧光性。     

Generation of hydrogen under visible light irradiation with enhanced photocatalytic activity of Bi2WO6/Cu1.8Se for organic pollutants under Vis‐NIR light reign

To make better use of solar light, a new Bi₂WO₆/Cu_1.8Se photocatalyst active to visible and near‐infrared light has been synthesized by a facile hydrothermal method. The composites were characterized by X‐ray diffractometry (XRD), scanning electron microscopy (SEM), UV‐vis diffuse reflectance spectroscopy (DRS), and photoluminescene (PL). The photocatalytic activities of Bi₂WO₆/Cu_1.8Se are evaluated by degrading Congo red solution and hydrogen generation from water. It was found that the molar percentage of Cu_1.8Se had great effects on the morphology and photocatalytic property of the Bi₂WO₆/Cu_1.8Se heterojunctions, and the composite with suitable molar amount of Cu_1.8Se exhibits much enhanced photocatalytic activity for Congo red degradation under visible and near‐infrared light irradiation and for hydrogen generation under visible light compared to Bi₂WO₆. The significant improvement photocatalytic activity of the composite could be attributed to its good light absorption, suitable band gap structure, and effective separation of photogenerated electron‐hole pairs of Bi₂WO₆/Cu_1.8Se heterojunction. This work presents an efficient multifunction photocatalyst owning the activity both for water splitting under visible light and for organic contaminants decomposition under visible‐near‐infrared light.     

植物纤维纸蜂窝制备的环境影响评价

利用CML环境影响评价方法,研究并比较了植物纤维纸蜂窝和传统芳纶纸蜂窝制备的环境影响。结果表明,针对所涉及的11个环境影响指标,植物纤维纸蜂窝低于芳纶纸蜂窝0.68 %~49.41 %;权重化结果表明,植物纤维纸蜂窝制备环境影响总体低于芳纶纸蜂窝18.77 %;制备芳纶纸蜂窝的环境影响主要来自于芳纶纸和电能的消耗;制备植物纤维纸蜂窝的环境影响主要来自于混杂纸和电能的生产。     

基于A*算法和人工势场法的移动机器人路径规划

针对复杂非结构化环境下移动机器人的路径规划问题,提出了将全局与局部规划算法相融合的路径规划方法。首先,对传统A*方法进行了有效的改进,新的A*算法能够完成机器人的路径规划任务,利用二次A*搜索方法得到了优化后的路径点,缩短了移动机器人的行驶路径。进一步,动态切点法可以有效地对已规划路径进行平滑处理;然后,综合考虑路径和环境的情况,采用改进的人工势场方法对移动机器人进行了局部路径规划,通过增设虚拟子目标的方法解决局部极小值问题,利用自适应步长调节算法对移动机器人的步长进行了动态优化;最后,针对不同场景,利用数值仿真将该算法与传统算法进行比较,结果表明该算法在不同环境路径规划的问题上具有一定的先进性和优越性。