激光熔覆复合涂层裂纹产生原因及控制研究进展

综述了激光熔覆复合涂层裂纹产生的原因及影响因素,并从基材预热、熔覆后涂层整体回火和重熔、梯度结构、工艺参数优化、熔覆材料及添加剂成分控制和辅助技术等方面归纳了控制裂纹的方法和途径。     

Purification and identification of antioxidant peptides from grass carp muscle hydrolysates by consecutive chromatography and electrospray ionization-mass spectrometry

Grass carp muscles were hydrolyzed with various proteases (papain, bovine pancreatin 6.0, bromelain, neutrase 1.5MG and alcalase 2.4L) to extract antioxidant peptides. The hydrolysates were assessed using methods of hydroxyl radical scavenging ability and lipid peroxidation inhibition activity. Hydrolysate prepared with alcalase 2.4L was found to have the highest antioxidant activity. It was purified using ultrafiltration and consecutive chromatographic methods including ion-exchange chromatography, multilayer coil high-speed counter-current chromatography, and gel filtration chromatography. The purified peptide, as a potent antioxidant, was identified as Pro-Ser-Lys-Tyr-Glu-Pro-Phe-Val (966.3 Da) using RP-HPLC connected on-line to an electrospray ionization mass spectrometry. As well, it was found that basic peptides had greater capacity to scavenge hydroxyl radical than acidic or neutral peptides and that hydrophobic peptides contributed more to the antioxidant activities of hydrolysates than the hydrophilic peptides. In addition, the amino acid sequence of the peptide might play an important role on its antioxidant activity.     

多分层对复合材料层合板自振特性的影响

基于Mindlin一阶剪切理论分项等参插值的有限元法, 建立了含多个分层损伤复合材料层合板自由振动分析的有限元模型和分析方法, 并采用线性接触模型模拟分层区域上、 下子板的相互作用。通过典型数值算例, 讨论了分层位置、 数目及板的边界条件诸参数对其振动特性的影响。结果表明: 分层位置沿板长方向变化时, 中间分层的频率变化范围较大, 表面分层变化较小, 但变化趋势基本相同; 沿层合板厚度方向, 多分层中最长分层的位置越靠近层合板中面, 则其对振动特性的影响越大; 多个分层位置较靠近层合板表面, 且板边界条件约束较弱时, 多分层与单分层对振动特性影响的差别不大, 此时, 可将多分层损伤层合板简化为单分层损伤层合板来进行振动分析。      

施用氨基酸水溶肥对于水稻生理生长及产量的影响

通过测定不同施肥处理下水稻茎蘖株高、干物质累积量、叶片叶绿素含量、植株吸氮量及产量对稻田施用氨基酸水溶肥进行评价.结果表明:通过施用氨基酸水溶肥,能够有效减少施肥过程中氮素损失,有力促进水稻生长指标的改善及产量的增长.总的来说,氨基酸水溶肥的使用,能够保证减氮的前提下,实现水稻一定程度增产的目标.本研究旨在为氨基酸水溶...     

基于蚁群算法的无功优化方法的研究

介绍了蚁群算法用于求解无功优化的步骤,在满足发电机无功功率、负荷节点电压等网络性能要求的前提下,以系统网损最小为目标函数,将发电机机端电压、变压器分接头和无功补偿设备出力为控制变量,建立求解无功优化问题的模型。最后通过仿真试验,验证了所提出方法的可行性。     

Hepatoprotective peptides purified from Corbicula fluminea and its effect against ethanol-induced LO2 cells injury

This study was focused on the purification, identification and mechanism of hepatoprotective peptides from Corbicula fluminea by using Sephadex G-15 chromatography, UPLC–MS/MS, oxygen radical absorbance capacity (ORAC) assay, cell experiment and molecular docking. Six identified peptides were synthesised chemically and subjected to evaluate hepatoprotective effect. ORAC value and hepaprotective effect against ethanol-induced LO2 cell injury in vitro were determined. The results showed that Tyr-Phe-Leu-Pro (YP-4) and Leu-Val-Tyr-Pro (LP-4) exhibited the strongest antioxidant activity and significantly increased the viability of ethanol-injured LO2 cells. These two peptides significantly reduced ROS levels and efficiently inhibited the decrease of mitochondrial membrane potential in ethanol-injured LO2 cells. Molecular docking revealed that YP-4 and LP-4 possess potential inhibitory activity on CYP2E1 and thus reduce ethanol-induced oxidative stress. It is suggested that YP-4 and LP-4 have good hepatoprotective effect against alcoholic liver injury.     

惯性系统故障诊断技术研究

本文简要介绍了故障诊断技术及其发展动态,指出了传统的完全基于检测数据的惯性系统故障诊断方法的局限性,提出了一种基于人工智能方法的惯性系统实时故障诊断方法,文中通过对惯性系统结构的分析,结合其自身的特点,建立了惯性系统实时故障诊断专家系统（ISRFDS）。     

基于改进物元可拓模型的水工混凝土耐久性影响因素分析

我国西北盐渍地区长距离输水工程由于冻融、干湿、盐侵等作用,对水工混凝土耐久性产生不利影响,直接影响输水稳定性及工程的安全运行与效益发挥。本文以甘肃省引大入秦工程输水建筑物为背景,基于室内加速试验,针对干湿-冻融和干湿-冻融-盐侵两种工况,研究质量损失率、抗压强度损失率、相对动弹性模量等耐久性指标变化情况,采用改进物元可拓模型综合分析矿粉、粉煤灰、引气剂、聚丙烯4种因素对水工混凝土耐久性的影响程度,并将计算结果与试验结果、实际状况开展比对分析。结果表明:在干湿-冻融工况中,粉煤灰对于水工混凝土耐久性的影响较矿粉、引气剂、聚丙烯显著,而在干湿-冻融-盐侵工况中,聚丙烯的影响最为显著,且最为敏感;采用改进物元可拓模型综合分析以上4种影响因素,影响程度依次为聚丙烯(3.450 9)＞粉煤灰(2.509 0)＞矿粉(2.447 2)＞引气剂(2.232 5),且根据等级变量特征值的大小可判断大循环后混凝土试块的状态,与实际状况相符。因此改进物元可拓模型可以综合分析盐渍区水工混凝土耐久性的影响因素,具有一定的实用价值。     

Effects of limited proteolysis and high-pressure homogenisation on structural and functional characteristics of glycinin

Glycinin was treated by limited proteolysis and/or high-pressure homogenisation in this work. The combined treatments significantly improved the solubility of glycinin, especially in acidic aqueous solution. Moreover, the modified glycinin had better emulsification capability and lower surface hydrophobicity. Electrophoresis analysis indicated more aggregates were formed after above treatments. But the laser scanning test showed the particle size of glycinin decreased. Compared with limited proteolysis, the combined treatments further increased the storage modulus and postponed the onset of glycinin gelation. The results of scanning electron microscopy showed that a fibrous curly structure was present in native glycinin. It was not found in modified glycinins. High-pressure homogenisation slightly shortened the onset of glycinin gelation, while limited proteolysis apparently postponed this behaviour. All the treatments formed weaker gels than native glycinin.     

基于自适应模糊PID的注塑机温度控制及仿真

为了对注塑机温度精确控制,针对注塑机温度在传统比例积分微分(PID)控制系统中存在的控制偏差大、调节速度慢等诸多不足的现状,提出将模糊控制器和PID控制器相结合,构造成一个自适应模糊PID控制器,运用MATLAB软件建立传统PID和自适应模糊PID控制器模型,对机筒温度进行仿真对比。设定200℃为给定温度,最终仿真结果显示,与传统PID控制器相比,自适应模糊PID控制器实现了注塑机温度的实时控制,达到了超调量小,升温快速及稳态无误差等要求。表明了自适应模糊PID控制器比传统PID控制器对温度的控制效果更加良好。