数论函数值分布问题中的Erds强度(Ⅰ)

本文考虑与素因子有关的加性函数ω(n)及Ω(n),证实了对于给正整数k,存在自然数n,使得在该点函数值超过左右两邻连续k个函数值的连乘积。     

Synthesis and tribology study of bi-alkoxy mono-thiophosphate triazine derivatives as additives in rapeseed oil

Series of triazine derivatives, 2,4-bi-alkoxy-6-(O,O‘-dialkyldithiophosphate)-s-1,3,5-triazine, were synthesized. Their tribological properties as lubricating oil additives in vegetable oil were evaluated using a four-ball tester. The results show that these triazine derivatives possess extreme pressure capacity, and they can improve antiwear and friction-reducing performance of base stock. The elements chemical states of the worn surface were estimated through X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM). The results show that a protective film containing sulphide, phosphate and some organic nitrogen compounds was formed on the worn surface during the lubrication process, and the film possesses extreme pressure and antiwear properties.     

添加剂对四氧化三铁粒子分散性的影响

以FeCl2·6H2O和FeCl3·H2O为原料,NH3·H2O为pH值调节剂,(NH4)2CO3为添加剂,采用水热法制备纳米Fe3O4粒子.产物经X射线衍射仪、透射电镜(TEM)和粒度仪检测分析.结果表明:用水热法制备纳米Fe3O4粒子的方法是可行的;由于共沉淀前驱体的不均匀性,当不加入添加剂时,得不到分散性好的Fe3O4粒子;当加入添加剂(NH4)2CO3时可以得到分散性好,颗粒均匀的Fe3O4纳米粒子,且产物是单相的Fe3O4纳米晶粒,结晶度完好,团聚程度低,粒度分布窄,平均粒径为45nm,比表面积达85m2 g.     

H_2SO_4溶液中F~-离子对Pb及Pb-Sb电极表面膜影响的研究

本文采用线性电位扫描、扫描电镜、X射线衍射等方法,研究了在 H_2SO_4溶液中添加F~-离子对Pb、Pb-Sb电极表面膜性能的影响。实验表明,在H_2SO_4溶液中添加 F~-离子,能使Pb、Pb-Sb 电极表面生成微晶结构的表面膜,并有助于表面膜底层中的pH升高及碱式硫酸铅含量增加,有利于提高Pb-Sb电极的耐腐蚀性。     

P_2O_5-Al_2O_3-H_2O系统的水热结晶

本文研究了某些碱性添加物对P_2O_5-Al_2O_3-H_2O系统水热结晶的影响。它们在一定程度上表现出结构导向作用,结晶产物依添加物之种类而变。本文还研究了Al_2O_3源、反应物组成、温度、结晶时间及高压釜内衬材质等因素的影响。实验结果表明,P_2O_5-Al_2O_3-H_2O体系的结晶行为比SiO_2-Al_2O_3-H_2O体系复杂得多,易生成多种结晶相,其中一些具有三维骨架结构。     

粘度添加剂顺丁胶实际使用性

将研制的顺丁胶粘度添加剂,调配成HC-14柴油机润滑油,通过江淮HF 440型发动机台架评定,和东风EQ140-1型汽车的行车试验,证明该剂能够实际使用。     

Estimation of detection threshold in multiple ship target situations with HF ground wave radar

A credible method of calculating the detection threshold is presented for the multiple target situations, which appear frequently in the lower Doppler velocity region during the surveillance of sea with HF ground wave radar. This method defines a whole-peak-outlier elimination (WPOE) criterion, which is based on in-peak-samples correlation of each target echo spectra, to trim off the target signals and abnormal disturbances with great amplitude from the complex spectra. Therefore, cleaned background noise samples are obtained to improve the accuracy and reliability of noise level estimation. When the background noise is nonhomogeneous, the detection samples are limited and often occupied heavily with outliers. In this case, the problem that the detection threshold is overvalued can be solved. In applications on experimental data, it is verified that this method can reduce the miss alarm rate of signal detection effectively in multiple target situations as well as make the adaptability of the detector better.     

基于转换的混合判断矩阵排序方法及比较研究

介绍加型一致性和积型一致性混合判断矩阵的概念,相应的定义了加型转换和积型转换。基于这两种转换,分别给出了将混合判断矩阵转换为互反判断矩阵的特征向量法和对数最小二乘法以及转换为互补判断矩阵的改进的最小方差法。通过算例说明了所给算法的可行性和有效性。从方法的难易,区分度及客观性三方面对现有方法做了对比分析。结果表明所给方法比较简洁和有效,具有很好的可靠性和实用性。     

PVDF成膜过程中溶剂分布的模型计算及其大孔形成机理

采用改进的浸入沉淀相转化法测定了聚偏氟乙烯(PVDF)/添加剂/二甲基乙酰胺(DMAc)铸膜液体系在成膜过程中溶剂的溶出量和溶出速度。实验过程中保持PVDF质量含量15%不变,采用的添加剂包括PEG200(聚乙二醇200)、PEG2000和聚乙烯吡咯烷酮(PVP)。拟合实验数据得到了溶剂在膜中的扩散系数,在此基础上以实测结果为边界条件,利用坐标变换后的费克扩散方程计算了膜内溶剂分布随时间变化的情况。根据计算结果与电镜照片,讨论了不同添加剂形成不同大孔长度的PVDF膜结构的现象。结果表明:膜内溶剂的浓度高、保留时间长有利于大孔向底部发展。