Investigation on formaldehyde gas sensor with ZnO thick film prepared through microwave heating method

ZnO nanopowders were prepared through microwave heating method. ZnO thick film sensors were fabricated by using ZnO nanopowders as sensing materials. The phase composition and morphology of the material particles were characterized by means of X-ray diffraction (XRD) and transmission electron microscopy (TEM), respectively. The gas-sensing properties of the sensors based on ZnO nano-materials were investigated. It was found that the sensor based on ZnO nano-materials (low power, 10× 10 min) exhibited very high responses to benzene and toluene when operating at 440 and 370 °C, respectively; but the sensor based on ZnO (low power, 10× 10 min) showed very low responses to benzene and toluene when operating at 205–215 °C. The sensor based on ZnO (low power, 10× 10 min) showed high response and good selectivity to dilute formaldehyde when operating at 210 °C; especially, the response to 0.001 ppm HCHO attained 7.4 when operating at 210 °C.     

Acetic acid gas sensors based on Ni2+ doped ZnO nanorods prepared by using the solvothermal method

Ni²⁺-doped ZnO nanorods with different doping concentrations are prepared via the solvothermal method. The doped ZnO nanorods are characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The amount of Ni²⁺ ions that enter the lattice of ZnO increases with increasing the Ni²⁺/Zn²⁺ molar ratio when the molar ratio of Ni²⁺/Zn²⁺ in the starting solution is lower than 3% and does not change obviously if the mole ratio of Ni²⁺/Zn²⁺ in the starting solution is in the range of 3-10 mol%. The effect of Ni²⁺ doping on the gas-sensing properties is investigated. The results reveal that the amount of Ni²⁺ has a great influence on the response (R_a/R_g) and the gas-sensing selectivity. The sensor based on 1 mol % Ni²⁺ doped ZnO nanorods (120 ℃, 10 h) exhibits a high response to acetic acid vapor, in particular, the responses to 0.001 ppm and 0.01 ppm acetic acid vapor reach 1.6 and 2, respectively. The response time and the recovery time for 0.001 ppm acetic acid are only 4 s and 27 s, respectively.     

稀土SO4^2—／ZrO2—TiO2复合固体超强酸对乙酸酯的催化合成研究

采用低温陈化法制得稀土SO4^2-/SrO2-TiO2复合固体超强酸,应用于乙酸酯类的合成中,在反应时间为2.5h,醇酸摩尔比为1：1.5时,催化剂用量为反应物质量的1.4%-1.5%,酯化率可高达97.4%。     

Spontaneous (Anti)meron Chains in the Domain Walls of van der Waals Ferromagnetic Fe5−xGeTe2

The promise of topologically vortex-like magnetic spin textures hinges on the intriguing physical properties and theories in fundamental research and their distinguished roles as high-efficiency information units in future spintronics. The exploration of such magnetic states with unique spin configurations has never ceased. In this study, the emergence of unconventional (anti)meron chains from a domain wall pair is directly observed at zero field in 2D ferromagnetic Fe_5−xGeTe₂, closely correlated with significant enhancement of the in-plane magnetization and weak van der Waals interactions. The simultaneous appearance of a large topological Hall effect is observed at the same temperature range as that of the abnormal magnetic transition. Moreover, the distinctive features of the (anti)meron chains and their collective dynamic behavior under external fields may provide concrete experimental evidence for the recent theoretical prediction of the magnetic-domain-wall topology and endorse a broader range of possibilities for electronics, spintronics, condensed matter physics, etc.     

微波小功率检定装置的设计及其不确定度分析

建立功率标准的目的是保证其量值的准确一致,要把功率标准的量值准确地传递到各级校准实验室的标准功率计上,高频和微波功率量值的传递方法有交替比较法、传递标准法和六端口法等.本文主要讨论的微波小功率检定装置采用的是传递标准法设计,通过对其不确定度进行分析,完全达到设计目的,可以对外开展功率计量检定.     

用转矩流变仪评价聚丙烯EPS30R的热稳定性

用HAAKE转矩流变仪RH600混合器,在高温、恒剪切力条件下动态法模拟挤出加工条件,通过测量转矩随时间变化曲线及感应时间,并通过树脂颜色变化共同评价聚丙烯EPS30R的热稳定性,同时对不同配方的聚丙烯热稳定性进行了比较,以检验其内部抗氧剂的使用效果。     

复合金属颗粒膜光学非线性增强因子的分析与计算

分析了金属颗粒膜的光学非线性增强效应，计算得到了Au和Ag颗粒膜的二次谐波增强因子FSHG与介质的介电常数的关系，以及在等离子体共振吸收频率处的三阶极化率增强因子F（3）.     

用共混方法提高注塑级HDPE的耐低温性能

实验讨论了加入LLDPE DFDA7042以后，HDPE DMD7006A耐低温性能的变化。认为DFDA7042对改善耐低温性能是有效的。可由原来的-60℃降至-85℃以下，而其它性能基本保持不变。     

齐鲁大棚膜料QLLP01的市场开发及展望

简要介绍了中国石化齐鲁股份有限公司开发的线性低密度聚乙烯QLLP01大棚膜专用料的性能及用 途,并与国内市场同类产晶以及相同用途的高压聚乙烯性能进行了对比,分析并展望了其市场前景,对其质量的进一 步提高及市场的进一步开发提出了建议。