聚乙烯催化剂用烷氧基镁载体的研究进展

基于烷氧基镁载体的Ziegler-Natta聚乙烯催化剂具有活性高、氢调性能好等优点,是目前聚烯烃工业中的研究热点。介绍了烷氧基镁载体的发展进程,综述了烷氧基镁载体的制备及改进方法,分析了烷氧基镁载体在催化剂制备过程中的作用,并对开发适用于乙烯聚合的烷氧基镁载体提出了展望。     

Fabrication of crescent-shaped ceramic microparticles based on single emulsion microfluidics

Ceramic microparticles have great potentials in various fields such as materials engineering, biotechnology, microelectromechanical systems, etc. Morphology of the microparticle performs an important role on their application. To date, it remains difficult to find an effective and controllable way for fabricating nonspherical ceramic microparticles with 3D features. This work demonstrates a method that combines UV light lithography and single emulsion opaque-droplet-templated microfluidic molding to prepare the crescent-shaped ceramic microparticles. By tailoring the intensity of UV light and flow rate of fluid, the shapes of microparticles are accordingly tuned. Therefore, varieties of crescent-shaped microparticles and their variations have been fabricated. After sintering, the crescent-shaped alumina ceramic microparticles were obtained. Benefitting from the light absorption and scattering behavior of most ceramic nanoparticles, this system can serve as a general platform to produce crescent-shaped microparticles made from different materials, and hold great potentials for applications in microrobotics, structural materials in MEMS, and biotechnology.     

涂装车间节水方案企划与实施

某涂装车间在现有节水措施的基础上，通过企划与实施一系列新的技术及精益管理措施，如，磷化出槽喷淋工艺优化、纯水制水率提升、空调冷凝水回用率提升、中水深度处理回用、用水分级管理等，将新鲜水用量从 15. 2 L/m2降至 11. 3 L/m2，达到涂装行业清洁生产评价指标体系（ 2016版）中的 I级标准 12 L/m²要求，处于国内领先水平。     

VUV photoluminescence properties of KSrPO4:Dy3+ phosphor

White-light-emitting phosphors based on phosphate host matrix, KSrPO_4 doped with Dy~(3+), were prepared by solid state reaction and their VUV luminescent properties were firstly investigated. The excitation band peaking at 125-153 nm corresponding to the absorption of PO_4~(3-) group exhibits very strong absorption. The phosphors emit warm-white luminescence under vacuum ultraviolet excitation of 147 nm, which consists of three main emission peaks located at 475, 570 and 662 nm, respectively.According to the luminescence and color chromaticity of the optimal sample KSrPO_4:1 mol%Dy~(3+),1.3 mol%Li~+, it can be a potential candidate for mercury-free fluorescent lamps.     

基于Hausdorff距离的光纤陀螺阈值滤波算法

要实现采矿机组的智能化，必须对采矿机械的位姿进行实时准确地控制。由于开采工作面环境复杂，可选用捷联惯性导航技术来实现对采矿机械的监测。光纤陀螺作为捷联惯导系统的核心元件，其随机噪声制约着惯性导航系统的精度。传统的建模滤波及小波消噪方法由于其自身的局限性，不能保证准确性和去噪效果。所以结合经验模态分解（Empirical Mode Decomposition，EMD），提出了Hausdorff距离（Hausdorff Distance，HD）筛选准则与阈值滤波相结合的去噪算法。该算法以本征模态函数（Intrinsic Mode Function，IMF）与原始信号概率密度函数（Probability Density Function，PDF）的Hausdorff距离为判别依据，对所有IMF进行筛选，之后引入阈值对筛选出的IMF进行滤波处理，最后将其与余项重构。通过试验比较了软硬阈值的滤波效果，确定了该算法采用硬阈值。为验证算法的有效性，将该算法与其他3种方法进行比较，仿真信号与实测陀螺静态漂移数据的试验结果表明了该方法的优越性，能够有效降低陀螺的各项随机误差。     

Physicochemical characteristics,antioxidant capacity and thermodynamic properties of purple-fleshed potatos dried by radio frequency energy

Abstract

The impacts of using radio frequency (RF) energy to dry purple-fleshed potatoes were investigated and compared to infrared radiation (IR) and microwave (MW) drying techniques. The gelatinization rate, color, flavor, morphological, and structural characteristics, thermodynamic properties, as well as antioxidant capacity were examined. The results indicated that the drying time of RF (70?min) and MW (21?min) were shorter than IR (105?min). The gelatinization ratio of MW, RF, and IR were 94.4?±?2.0, 88.3?±?1.4, and 64.5?±?1.1%, respectively. The degree of crystallization of purple-fleshed potato powder decreased with all three drying methods. RF-dried potatoes were able to retain higher polyphenols (loss rate: 4.3%), total anthocyanin (3.7%), and total flavonoid content (35.1%), whereas IR showed the lowest retention. The content of polyphenols also decreased significantly. Furthermore, after RF heating, the scavenging of free radicals was higher compared to MW and IR.     

OMS-2催化剂成型工艺研究及其在印染废水处理中的应用

以OMS-2粉体催化剂为基础,对催化剂进行挤出成型,考察粘结剂种类、粘结剂用量、润滑剂和孔结构改进剂用量、焙烧温度对成型催化剂机械强度的影响。得到最佳成型工艺条件为,粘结剂硅溶胶用量为OMS-2粉体催化剂质量的105%～110%、辅助粘结剂纳米ZrO_2用量为OMS-2粉体催化剂质量的30%～35%、润滑剂田菁粉用量为OMS-2粉体催化剂质量的2. 5%～3. 0%、孔结构改进剂柠檬酸用量为OMS-2粉体催化剂质量的5%～6%,焙烧温度450℃。成型后催化剂机械强度可达150 N·cm~(-1),满足工业化应用对催化剂强度的要求。将成型催化剂应用于催化湿式氧化印染废水处理,经过432 h活性评价时间,COD平均去除率约91. 6%,反应结束后催化剂结构完整,平均机械强度约144 N·cm~(-1),表现出良好的水热稳定性。     

Multi-objective layout optimization for an orbital propellant depot

Structural and Multidisciplinary Optimization - The overall layout optimization design of an orbital propellant depot involves the optimization of shape, size, and positions of propellant tanks in...     

湾图沟煤矿高强度采动巷道稳定性评价研究

针对高强度采动巷道围岩控制难题，从实验室岩样尺度和现场巷道尺度研究了湾图沟煤矿13405工作面回风平巷围岩稳定性特征。结合单轴压缩试验和声波测试分析了干燥、自然及饱和状态下3组岩样的力学行为差异特征。利用钻孔成像，分析了高强度采动影响巷道围岩裂隙发育分段特征。结果表明:干燥、自然及饱和状态下岩样的单轴抗压强度和弹性模量依次降低，水分的存在极大地降低了岩石的强度和刚度。实煤体段围岩仅在深度1 m范围内发现少量纵向裂隙。高静压段两帮维护效果较差，煤帮裂隙极为发育，存在高量值的离层。动压段巷道顶板完整性较好，两帮均发现较大离层，且超出了锚杆正常锚固范围，严重影响了巷道锚固结构的稳定性。