细圆管内氧化铜颗粒悬浮液流动与对流换热的实验研究

实验研究了氧化铜纳米悬浮液在内径为0.68mm不锈钢细圆管内迫流动和对流换热。氧化铜纳米颗粒悬浮液的质量分数W为0.02-0.06，分别去离子水和水－纳米颗粒悬浮液的流动，传热特性进行了实验测定。实验结果表明：所研究尺度下，层流向湍流过渡早于常规大尺度流动，悬浮液的压降要大于去离子水的；纳米颗粒的质量分数越大，压力降也越大，悬浮液的对流换热系统随颗粒质量分数的增大而增大。     

最小费用流算法在配电网网络重构中的应用

将图论中的最小费用流算法用于求解配电网网络重构问题,寻求以压损耗最小为目标的合理的开环运行方式,验算表明,该算法简单,快速、有效。。     

Effect of Al doping on electrochemical performance of NaTi2(PO4)3/C anode for aqueous sodium ion battery

The Na_1+xAl_xTi_2?x(PO₄)₃/C (x?=?0, 0.05, 0.10, 0.20) composites serving as anode for aqueous sodium ion battery are successfully synthesized through a facile sol–gel route. The results indicate that introduction of proper amount of aluminum has no obvious effect on the structure and morphology of NaTi₂(PO₄)₃/C. Among the four synthesized samples, Na_1.1Al_0.1Ti_1.9(PO₄)₃/C (NATP-0.10) exhibits the best electrochemical performance. NATP-0.10 delivers a discharge specific capacity of 115.8, 106.9, 98.4, and 89.1 mAh g^?1 at 2, 5, 10, and 20 C rate, respectively, and still retains 114.7 mAh g^?1 when the current density comes back to 2 C. Additionally, NATP-0.10 exhibits an initial discharge capacity of 102.9 mAh g^?1 and still retains a reversible capacity of 90.1 mAh g^?1 at 10 C rate after 200 cycles. Cyclic voltammetry and electrochemical impedance spectroscopy demonstrate the better electrochemical performance of NATP-0.10 is due to the faster sodium migration and enhanced electrochemical kinetics.

Graphical abstract

Al doping Na_1+xAl_xTi_2?x(PO₄)₃/C (x?=?0, 0.05, 0.10, 0.20) composites were firstly used as anodes in aqueous SIBs. The electrochemical performance of NaTi₂(PO₄)₃/C has been improved by introducing a proper amount of Al.

     

国内首条两窑一塔烟气脱硫系统的应用

本文详细介绍了国内首条两窑一塔、烟塔合一回转窑烟气脱硫系统在生产线上的具体应用,结合老厂的特殊现状,通过相关工艺技术创新和生产实践完善,为一些水泥企业的烟气治理方案提供了可借鉴的样板模式。     

氯离子和电偶腐蚀对碳钢在热钾碱溶液中腐蚀的影响

研究了Cl-对碳钢和不锈钢在(K2CO3+KHCO3+ V2O5)溶液中腐蚀的影响,结果表明Cl-对阳极钝化曲线所示的腐蚀电位、钝化区间、过钝化电位和析氧过程无明显影响,未见试样有孔蚀的迹象.但随着Cl-离子浓度增大,其维钝电流密度也增大.90℃时,不锈钢-碳钢在此溶液中构成电偶腐蚀时,测得碳钢腐蚀速率为0.064 mm/a,比未成偶对时碳钢的腐蚀速率大一倍.90℃时,将已钝化的不锈钢-碳钢在(K2CO3+KHCO3)溶液中构成电偶腐蚀时,测得碳钢腐蚀速率为4.0 mm/a,比含有V2O5溶液中碳钢的腐蚀速率大64倍.     

PEG模板组装纳米TiO2多孔薄膜的制备

以钛酸丁酯为无机原料,加入高分子表面活性剂聚乙二醇(PEG)作模板剂,采用溶胶-凝胶工艺和浸渍-提拉技术在玻璃基片上制备了孔径在10 nm～1 000 nm范围内可调的纳米TiO2多孔薄膜.通过SEM,AFM,UV-VIS和N2吸附等测试手段对薄膜的多孔结构进行了表征.结果表明,通过调节溶胶中PEG的分子量和浓度,可以控制薄膜中孔的孔径及孔分布密度,有效提高薄膜的比表面积.此外还考察了提拉速度和焙烧制度对薄膜多孔结构的影响.     

Evaluation of structural reliability of mems device in digital video disk systems

In this paper, we describe the reliability evaluation for MEMS devices, especially designed tbr DVD(Digital Video Disk) application. These MEMS devices are fabricated as a mirror plane (shutter plane) used in DVD data picking up. This micromachined annular shutter mirror (ASM) acts as an adjusting means of the numerical aperture. The electrostatic force can drive the upper plane up and down for focusing or defocusing of incident laser beam to the selected recording plane. So we need to evaluate the micromechanical properties of thin film structural materials to ensure the reliability of those MEMS devices. For those, we perfl)rm the fatigue tests onto the devices in the conditions of much accelerated than those of normal driving. The applied electrostatic force can induce the change of the thin film properties, and those are observed by direct and indirect methods (XRD and electrical system). And then, we compare the fatigue effects with electrical, optical data from the intentionally-fatigue-applied specimen and as-fabricated one under accelerated conditions. Consequently, we can estimate the structural reliability and will provide the effective suggestion data for the fabrication of stable mirror material before commercialization.     

粒径与加热速度对金属Al氮化过程的影响

在氮气流量为55 ml/min条件下,分别以5,10,15 ℃/min的加热速率对不同粒径(d_(50)为62,29,7.5μm)的金属Al粉进行了TG-DTA分析和反应活化能的研究.结果表明:在相同的实验条件下,随Al粉粒径的减小和加热速率的增大,生成AlN的反应活化能降低;在N_2流量55 ml/min和加热速率5 ℃/min条件下,d_(50)= 29 μm和d_(50) =7.5 μm Al粉生成AlN的主放热峰温比d_(50) =62 μm Al粉的分别可降低140和250 ℃.在N_2流量55 ml/min条件下,d_(50)= 7.5 μm Al粉以10和15 ℃/min为加热条件的氮化反应速率比5 ℃/min的提高0.9和1.7倍.Al粉反应生成AlN的全过程,主要由界面反应和内扩散反应交替完成,且整个反应过程应为扩散机制控制.     

熔融石英陶瓷材料的晶化抑制研究

以粒径〈0．16mm的熔融石英颗粒为原料，以硼酸、碳化硅、氮化硅、水玻璃为晶化抑制剂，以聚乙烯醇（浓度1％）为结合剂，试样成型压强为20MPa，试样经1200℃保温2h烧成，对烧后试样进行1500℃保温1h的强化脱玻处理、RT～1300℃的差热分析以及RT～1300℃的热膨胀测定。试验发现：引入碳化硅或水玻璃对熔融石英的析晶抑制作用不明显，而引入5％的硼酸或引入3％的氮化硅可有效抑制熔融石英的析晶。     

食品类专业《仪器分析》教学内容的探讨与完善

《仪器分析》是食品类相关专业本抖生的专业基础课,目前存在着无专业性教材,且与生产和科研实际脱节,实验教学经费投入不够,综合性实验训练不足的现象。文章根据多年教学经验,针对食品类专业的特色,从实际需求出发,对《仪器分析》理论和实验教学内容提出了建议,并对教学方式提出改进。