离子色谱-电导法检测酱油中氯化钠的含量

该研究采用灰化预处理+离子色谱-电导法检测酱油中食盐的含量，并与莫尔法、电位滴定法进行比较。结果表明，莫尔法存在滴定过量问题，电位滴定法对温度等外界环境条件和仪器操作要求苛刻，而离子色谱-电导法具有操作简便快速并具有较好的准确度和精密度。实验结果表明，氯化钠含量处于11.56～11.61 g/100 mL之间，回收率实验结果为96.00%～102.10%，相对标准偏差为0.089%。干扰实验对结果无明显影响，且能同时测定多种离子，可用于成品酱油中氯化钠含量的检验。     

基于哈希锁定的网络传输异常序列监测仿真

为有效提升传统网络传输异常序列监测方法的处理效率,提出基于哈希锁定的网络传输异常序列监测方法。利用随机投影的哈希函数将高维空间数据转换为低维空间数据,并利用网络传输序列的多元数量值函数,组建网络传输结构模型。对网络传输结构模型进行流量时频采样以及时间序列分析,结合FIR滤波器对其进行流量抗干扰处理,通过高阶累计的振荡衰减,对输出的滤波数据进行特征搜索及提取,实现基于哈希锁定的网络传输异常序列监测。仿真结果表明,所提方法具有较强的抗干扰性,并且能够确保网络的稳定运行。     

BHA轴向磁干扰对方位测量误差的影响——基于人工磁场模拟方法

井下钻具组合（BHA）磁化形成的轴向磁场干扰是定向组件磁方位测量的一个重要的误差因素。为了对该误差因素进行独立分析，建立了大型三轴亥姆霍兹线圈人工磁场系统作为研究环境，使用不同磁通量的多个磁化组件作为干扰源研究在理想环境中轴向干扰磁场对定向组件的影响，并在此基础上提出了一种估算磁化组件磁极强度和校正轴向干扰的方法，通过改变空间姿态和三轴亥姆霍兹线圈磁场强度，分析了在不同井斜角、方位角和磁倾角的井眼轨迹中，轴向磁干扰对定向组件方位测量误差的影响，最后证明了校正磁性组件的轴向干扰方法，可以有效地提升BHA定向组件的方位测量精度。     

开关磁阻电机结构性转矩脉动抑制方法

开关磁阻电机具有结构简单、成本低和调速范围广等优势,但其双凸极结构和控制器的开关特性,导致存在转矩脉动现象,使得抑制转矩脉动成为焦点问题。首先从开关磁阻电机的结构和运行机理出发,针对线性解析方法难以分析转矩特征的问题,建立电机有限元模型求解出转矩特征并进行样机验证试验。分析样机结构参数对转矩脉动的影响,针对结构参数耦合问题,选择NSGA-Ⅱ算法在参数优化平台上对样机结构参数进行多目标寻优,在保证优化后样机的转矩脉动系数和平均转矩均优于初始电机的条件下,最终获得样机最优化结果。结果表明,不同结构参数对电机转矩的影响有较大的差异,对结构参数的优化能有效地抑制转矩脉动,该参数优化方法可以为开关磁阻电机结构性转矩脉动抑制提供参考。     

Combustion enhancement and inhibition of hydrogen-doped methane flame by HFC-227ea

Hydrogen enriched with compressed natural gas is an efficient and environment-friendly gaseous fuel. However, the safety issues of mixture and the method to control or weaken their combustion are highly concerned. To explore the inhibition effect of halogenated fire suppressants on the mixture, the effect of HFC-227ea on the laminar premixed methane/air flames, with different fractions of H₂, have been studied. Burning velocities have been measured with constant-volume combustion chamber and kinetically modelled a recently assembled kinetic mechanism. The fractions of H₂ influence the enhancement and inhibition effect of HFC-227ea, and it is less effective with the lean mixture. In stoichiometric condition, HFC-227ea showed good inhibition effect on the mixture flames. The HFC-227ea increased the burning velocities of CH₄-0% H₂-air and CH₄-10% H₂-air flames at leanest condition, whereas the increased burning velocity arising from HFC-227ea not occurred as the addition of H₂ above 20%. Experimental results coincided well with numerical results, however the agreement was poor for the leanest flames at low agent loading. Lastly, kinetic mechanism analysis was used to interpret the combustion enhancement and inhibition effect of hydrogen-doped methane flame by HFC-227ea.     

基于光储频的超宽带相控阵干扰系统设计

瞄准现代化信息战争中有源电子干扰超宽带、大功率、多目标作战能力需求,将超宽带光储频技术与有源相控阵相技术相结合,构建并设计了一套基于光储频的超宽带相控阵干扰系统。基于光延时网络结合波分复用技术实现超宽带光储频,并通过实时时间延时技术实现超宽带有源相控阵发射多波束合成。系统具有大有效辐射功率发射、同时多波束发射以及超宽带瞬时干扰特性,有效解决了传统数字储频、非功率合成体制有源电子干扰系统有效辐射功率小、多波束能力不足、干扰带宽受限等问题。     

A two-stage vision-based method for measuring the key parameters of ball screws

Ball screws are crucial for improving the reliability and interchangeability of transmission mechanical systems; however, existing contact measurement methods that utilise stylus contact are not efficient, which precludes their use for rapid in-situ geometry evaluation. This paper presents a vision-based two-stage method for rapid measurement of key parameters (raceway arc radii and centre distance) of ball screws. The edge contour information is extracted from the acquired image using the dual-tree complex wavelet transform and non-maximal suppression. In the matching stage, a shape-matching algorithm is used for detecting approximate geometrical centres of raceway arcs. The refinement stage, on the other hand, is implemented for acquiring precise dimensional results. Furthermore, the method of averaging multiple measurements is performed to suppress random noise. A comparative experiment is presented to validate the robustness of the proposed method. Based on experimental results, the calculated mean absolute errors in the measurement of the two raceway arc radii and the centre distance are found to be 0.0082 mm, 0.0079 mm and 0.0055 mm, respectively. This study therefore paves the way for key parameter measurement without removing ball screws.