铝碳质长水口用低铝抗氧化涂层的研制

为抑制铝碳质长水口使用过程中石墨的氧化，其表面会涂覆含 20%~30%Al₂O₃的抗氧化涂层，但切割丝钢等特种钢冶炼过程必须严格控制钢液中夹杂的 Al₂O₃的含量，因此需要制备低氧化铝含量的抗氧化涂层。本文通过调节涂料组成、加水量和水玻璃加入量制备了低铝抗氧化涂层，并利用扫描电镜分析了抗氧化实验后试样断口的显微结构。结果表明：以粘土粉、钾长石粉和硅砂为主要原料，添加 10%硼砂的涂料可在 800 ℃形成良好的釉层，此时涂料中 A12O3的含量可降至 12%，得到了低铝涂料；当加入占涂料质量 80%的水和 40%的水玻璃时，涂层具有最佳的涂覆性能和抗氧化性能，涂层和长水口基体结合致密，保护了长水口中的石墨不被氧化。     

Fragmentation and film growth in supersonic nanoaggregate aerosol deposition

Aerosol deposition with gas phase-synthesized chain-like nanoaggregates can yield dense coatings from the impaction of particles on a substrate; however, dense coating formation is not well understood. Here, we study coating consolidation at the single nanoaggregate level. Flame spray pyrolysis-made tin oxide nanoaggregates are mobility (size) filtered, accelerated through a de Laval nozzle, and impacted on alumina substrates. TEM images obtained from low velocity collection and supersonic deposition are compared via quantitative image analysis, which reveals that upon supersonic impact nanoaggregates fragment into smaller aggregates. This suggests that fragmentation is a key step in producing coatings denser than the depositing nanoaggregates themselves. We supplement experiments with detailed particle trajectory calculations, which show that the impact energies per atom during nanoaggregate deposition are below 0.2 eV/molecule. These results suggest that fragmentation can only occur at locations where nanoaggregates bonded by van der Waals and capillary interactions.     

Facile synthesis of Ni doped CoWO4 nanoarrays grown on nickel foam substrates for efficient urea oxidation

Urea electrolysis is a promising technology for hydrogen production, which can alleviate environmental pollution of urea-rich wastewater. It's worth noting that electrochemistry activity can be significantly improved by reasonably regulating the electron configuration around the active site for the doped materials. In this work, a series of well-tuned Ni doped CoWO₄ nanoarrays on Ni foam supports have been prepared through a typical hydrothermal approach for the first time. Moreover, the resulting Ni–CoWO₄-2 material significantly promotes urea oxidation performance with an applied potential of 1.35 V at 50 mA cm^?2, which is lower than that of water oxidation reaction (1.60 V). Density functional theory results suggest that the Ni doped CoWO₄ has larger urea adsorption energy compared with CoWO₄ and the CO(NH₂)₂ molecule is strongly adsorbed on surface of Ni doped CoWO₄, which is beneficial to accelerate the kinetics of the reaction and improve the electrocatalytic activity of the urea electrolysis.     

A1与A2 β-酪蛋白酸奶产品特性的比较

探究分别含有A1、A2两种β-酪蛋白牛乳制成的搅拌型和凝固型酸奶产品特性的区别。持水力结果表明，A1 β-酪蛋白酸奶（凝固型和搅拌型）的持水力大于69%，A2 β-酪蛋白酸奶（凝固型和搅拌型）的持水力大于65%。质构特性的结果显示，凝固型酸奶差距更为明显，A1 β-酪蛋白酸奶的硬度和稠度分别比A2 β-酪蛋白酸奶高41.4%和59.8%。此外，A1 β-酪蛋白酸奶黏性优于A2 β-酪蛋白酸奶。流变学特性与微观结构结果显示，A1 β-酪蛋白酸奶的滞后回路面积较A2 β-酪蛋白酸奶小14.6%，说明A2 β-酪蛋白制成的酸奶结构更易于被破坏，网状结构更为稀疏。本实验为A2 β-酪蛋白牛乳在酸奶制品的应用及实际生产提供一定理论支持。     

Influence of water content in mixed solvent on surface morphology,wettability, and photoconductivity of ZnO thin films

ZnO thin films have been synthesized by means of a simple hydrothermal method with different solvents. The effect of deionized water content in the mixed solvents on the surface morphology, crystal structure, and optical property has been investigated by scanning electron microscopy, X-ray diffraction, and UV-Vis spectrophotometer. A large number of compact and well-aligned hexagonal ZnO nanorods and the maximal texture coefficient have been observed in the thin film, which is grown in the mixed solvent with x = 40%. A lot of sparse, diagonal, and pointed nanorods can be seen in the ZnO thin film, which is grown in the 40-mL DI water solution. The optical band gap decreases firstly and then increases with the increase of x. Reversible wettability of ZnO thin films were studied by home-made water contact angle apparatus. Reversible transition between hydrophobicity and hydrophilicity may be attributed to the change of surface chemical composition, surface roughness and the proportion of nonpolar planes on the surface of ZnO thin films. Photocurrent response of ZnO thin films grown at different solvents were measured in air. The response duration of the thin film, which is grown in the solvent with x = 40%, exhibits a fast growth in the beginning but cannot approach the saturate current value within 100 s. The theoretical mechanism for the slower growth or decay duration of the photocurrent has been discussed in detail.     

Predicted Trans-Acting siRNAs in the Human Brain

Endogenous small non-coding RNAs play pivotal roles in regulating gene expression in eukaryotes. Many studies have investigated the function and molecular mechanism of microRNAs in the development and disease of various organisms via mRNA repression of protein-coding genes. Recent findings indicate microRNAs might trigger the generation of trans-acting small interfering RNAs (ta-siRNAs). The interaction among different types of small RNA molecules reveals an even more complicated and elaborate pattern of RNA regulation during gene expression than previously thought. We developed a method for mining ta-siRNA sequences and evaluated the performance of our novel method using data from Arabidopsis thaliana. Additionally, using small RNA and degradome data for the human brain, we identified 155 small RNAs that satisfied ta-siRNA characteristics. The DRAXIN and ATCAY genes, which are preferentially expressed in the human brain, were predicted to be the targets of 12 potential ta-siRNAs.     

黄河故道兰考段地下水水化学特征

为了基本查明黄河故道兰考段地下水水化学特征,采集代表性地下水样进行了27项无机指标和37项有机指标测试,结果表明,兰考县地下水水化学类型多数为HCO3-Na.Ca.Mg型水,咸水、微咸水、高铁、高锰、高氟等原生劣质水均有分布;其中,黄河故道区水质较好,背河洼地区和县城周围水质较差;县城周围浅层地下水已经受到污染,污染组...     

MnO_x/Ce_(0.5+x)Zr_(0.4–x)La_(0.1)O_(1.95)-Al_2O_3 catalysts used for benzene catalytic combustion

Complete oxidation of benzene over supported manganese oxides catalysts was studied.Composite supports Ce0.5+xZr0.4–xLa0.1O1.95-Al2O3 (x=0,0.1,0.2,0.3,0.4),and CeO2-Al2O3 were prepared by co-precipitation method,and manganese oxides (MnOx) catalysts were prepared by incipient wetness method.Catalytic activity was performed in a conventional fixed bed flow reactor.Among these catalysts,MnOx supported on Ce0.8Zr0.1La0.1O1.95-Al2O3 was found to have the highest catalytic activity for benzene oxidation.The comp...     

Effect of solution concentration on surface morphology and photocatalytic activity of ZnO thin films synthesized by hydrothermal methods

ZnO thin films were synthesized via hydrothermal method on silicon substrate at various solution concentrations. The thin films were characterized by X-ray diffraction, field-emission scanning electron microscope and UV–Vis spectrophotometer. The results show that the thin films are polycrystalline with wurtzite hexagonal structure. The T _c values of (101) surface of the thin film increase from 0.929 to 1.840 at first, and then decrease to 0.779 with increasing solution concentration. The preferential orientation along the (101) crystal surface can be controlled by changing the solution concentration. Solution concentration has a significant effect on surface morphology of the thin films. The optical band gap of the thin films decreases, when the solution concentration of zinc nitrate hexahydrate increases from 0.01 to 0.06 mol/L and then increases when the solution concentration of zinc nitrate hexahydrate further increases to 0.08 mol/L. Photocatalytic activity of the thin films on degradation of methyl orange under UV light irradiation was studied in detail. The ZnO thin film with many cracks prepared from 0.01 mol/L shows the higher photocatalytic activity but the tower-like ZnO thin film prepared from 0.08 mol/L reveals the lower photocatalytic activity. Therefore, the photocatalytic activity of the thin films are mainly relate to surface morphology and crystallographic orientation.