碱溶酸沉法提取血红铆钉菇中总黄酮的技术研究

为鉴定血红铆钉菇中营养成分,进一步探讨其总黄酮提取工艺。以血红铆钉菇总黄酮提取率为考察指标,首先通过碱溶酸沉法和索氏提取血红铆钉菇总黄酮,利用薄层色谱鉴定总黄酮物质的性质和纯度,进一步研究提取试剂、温度、时间和固液比等单因素条件对血红铆钉菇总黄酮提取率的影响。研究结果表明:血红铆钉菇提取物为黄酮类物质,其总黄酮的提取条件为粗粉颗粒40目、提取试剂pH为9、固液比1∶10、提取时间30 min、提取温度60℃、结晶时滤液pH为3、时间4 h,最终得率为9.5%。本文评价了不同影响因素下碱溶酸沉法提取血红铆钉菇总黄酮物质的提取条件,研究结果具有较高的推广及应用价值。     

钛掺杂BiFeO3光催化剂的制备及其催化性能

用溶胶-凝胶法制备钛(Ti)掺杂BiFeO₃纳米颗粒(Ti-BiFeO₃), 研究不同煅烧温度对Ti掺杂BiFeO₃结构调控及光催化性能的影响, 用X射线衍射（XRD）、 扫描电子显微镜（SEM）、 能谱分析（EDS）、 紫外-可见（UV-Vis)光谱技术对颗粒的相结构、 形貌、 原子比例、 光催化性能等进行测试及分析, 并以罗丹明-B为目标降解物, 对Ti掺杂BiFeO3光催化性能进行研究. 结果表明: Ti掺杂BiFeO₃样品在不同煅烧温度均出现Bi₂Fe₄O₉相; 煅烧温度可对Bi₂Fe₄O₉的含量进行调控, 在650 ℃煅烧样品中含有适量的Bi₂Fe₄O₉相, 能有效提高Ti掺杂BiFeO₃的光催化活性, 且具有较高的降解活性, 60 min内降解效率达85%.     

基于卡口数据的机动车出行生成模型

针对出行生成预测方法需要耗费较多的人力物力调查、数据精细化程度较低的现状,综合考虑土地利用类型、土地利用混合度、可达性等指标,使用海量卡口数据获取机动车出行生成量并建立逐步回归分析模型;通过与灰色预测模型耦合的方法对回归模型中人口、就业岗位等灰色变量进行预测,将预测值代入所得线性回归方程得到相应土地类型目标年机动车出行生成的预测量.以武汉市为案例研究对象,分析了典型土地利用类型上的机动车出行发生和吸引的主要影响因素,并对预测值予以验证.研究结果表明:不同土地利用类型的机动车出行产生和吸引的关键影响因素不尽相同,本模型平均预测精度在0.932,可为交通规划用地布局等提供参考.     

基于莱维飞行和高斯分布的改进教与学算法

教与学优化算法(TLBO)是一种基于课堂教学学习过程的新型元启发式算法,在解决众多科学和工程问题方面表现出了卓越的性能.然而,许多研究表明,TLBO在问题的求解过程中搜索能力较差,算法易陷入局部最优.针对这一问题,提出了一种基于莱维飞行和高斯分布的教与学优化算法(LTLBO-GD).一方面,将原有的TLBO算法与莱维飞行策略相融合,在教学阶段前期增强老师的学习能力,选择出教学能力突出的老师.另一方面,在学习阶段加入高斯分布局部搜索算子,引导学生进行自学习模式,高斯分布主要是对班级中某一维度进行搜索,从而增强算法单维搜索能力和收敛速度.测试实验结果表明,LTLBO-GD算法在求解精度和收敛速度上都有了显著的改善,并且在求解效果上也明显优于TLBO算法,在典型的标准测试函数优化问题中其优越性更加突出.     

基于BP神经网络CFRP约束混凝土抗压强度预测

为研究BP神经网络对CFRP约束混凝土抗压强度的预测能力以及神经网络模型的输出性能,在大量的实验数据基础上,建立了CFRP约束混凝土抗压强度的BP神经网络预测模型,探讨了不同数据组合对神经网络模型预测精度的影响;基于神经网络理论,将高精度BP神经网络模型生成了可方便应用的一般公式和简化公式,并与已有经验公式进行了对比分析.研究结果表明:BP神经网络能够很好地挖掘输入输出参数的数据信息,得到高精度的预测模型;相比于传统回归模型,用purelin代替sigmoid做传递函数推导得到的简化线性方程式仅增加了一项常数项,其预测值与试验值比值的平均值为1.011,变异系数为0.112,具有更高的预测精度和稳定性.     

焊接速度对自适应双轴肩搅拌摩擦焊接Al–Mg合金接头微观组织和机械性能的影响

The butt welds of 4-mm thick 5A06 aluminum alloy plates were produced by adjustable-gap bobbin-tool friction stir travel with travel speeds of 200, 300, and 400 mm/min in this study. The microstructure was studied using optical microscopy and electron backscatter diffraction (EBSD). Tensile tests and microhardness measurements were performed to identify the effect of the travel speed on the joint mechanical properties. Sound joints were obtained at 200 mm/min while voids were present at different positions of the joints as the travel speed increased. The EBSD results show that the grain size, high angle grain boundaries, and density of geometrically necessary dislocations in different regions of the joint vary depending on the recovery and recrystallization behavior. Specific attention was given to the relationship between the local microstructure and mechanical properties. Microhardness measurements show that the average hardness of the stir zone (SZ) was greater than that of the base material, which was only affected slightly by the travel speed. The tensile strength of the joint decreased with increasing travel speed and the maximal strength efficiency reached 99%.     

Review of the fatigue behavior of hard coating–ductile substrate systems

With the wide application of coating materials in aerospace and other fields, their safety under fatigue conditions in service is important.However, research on the fatigue properties of ceramic hard coatings started late, and a unified standard is yet to be established to evaluate the fatigue life of hard coating–ductile substrate systems.Studies also present different opinions on whether coatings can improve or reduce the fatigue life of substrates.In this paper, the influence of the properties of ceramic coatings on fatigue performance is reviewed, and the effects of coating on the mechanism of fatigue crack initiation in substrates are discussed, aiming to help readers understand the fatigue behavior of hard coating–ductile substrate systems.     

Effect of superplastic deformation on precipitation behavior of sigma phase in 3207 duplex stainless steel

Owing to excellent strength, toughness and corrosion resistance, duplex stainless steels(DSS) are widely used in constructional and petrochemical applications. Sigma phase, which has detrimental impact on the properties, is readily precipitated during hot working of DSS. However, precipitation behavior of sigma phase during superplastic deformation, which is the most significant processing method of DSS, is still unclear. In the current study,the effect of superplastic deformation on the precipitation behavior of sigma phase was investigated in 3207 duplex stainless steel. The result shows that superplastic deformation could prevent sigma phase precipitation generally by increasing mobility of grain boundaries and decreasing misorientation of the sigma phase boundaries, resulting in some sigma phase precipitated on the twin boundaries. Most of the sigma phase precipitated on ferrite-austenite interface with misorientation of 20–25°, while it precipitated in ferrite or austenite with the misorientation of 40°–45°. The orientation relationship between sigma phase and matrix matched well in austenite and on the ferrite/austenite interfaces, while it showed a small misfit in ferrite. The prevention effect of the superplastic deformation on the sigma phase precipitation was beneficial to quasi stable deformation stage,resulting in longer elongation.     

三水合艾司奥美拉唑镁反应结晶过程晶型控制

对三水合艾司奥美拉唑镁制备过程中晶型控制进行研究,同时对产物的粒度分布等性质进行了工艺优化实验。通过X射线粉末衍射表征产物晶型,借助于二维在线成像系统监测三水合艾司奥美拉唑镁反应结晶过程中的晶体形貌变化,运用马尔文激光粒度仪辅助监测晶体的粒度分布变化。考察了结晶温度、反应物的浓度等因素对三水合艾司奥美拉唑镁晶型与晶习的影响。结果表明,三水合艾司奥美拉唑镁结晶方式为球形结晶,结晶温度是影响晶型的关键因素,优化后的结晶温度为25 ℃。优化后的工艺可以制备晶型固定、粒度分布均匀、平均粒度大的三水合艾司奥美拉唑镁药物颗粒。     

基于 NSDTCT 与稀疏表示的红外和微光图像融合

针对传统融合方法信息缺失较多与连续性较差等问题,提出了一种基于非下采样双树复轮廓波变换（NSDTCT）与稀疏表示的红外和微光图像融合方法。利用NSDTCT进行多尺度分解获得低频成分和高频子带成分,引入稀疏表示理论,构建低频成分和高频成分的融合模型,将图像融合分别转化为对应稀疏编码的融合,低频和高频成分稀疏表示系数分别根据加权平均和多方向对比度准则进行融合。进行对比实验,选用平均梯度（AG）、标准差（STD）、互信息（MI）、边缘保持度（QAB/F）、结构相似度（SSIM）这5种客观指标,结果较传统方法分别提升2.1%、3.3%、16.1%、6.6%、8.5%以上,表明该方法能够有效保留红外微光图像信息,提高融合图像连续性和成像质量。