Study on the Ballistic Performance of Multiply Wadded Through-the-thickness Angle-interlock Fabric Reinforced Composites

Applied Composite Materials - The paper presents a study on the ballistic performance of 3D woven wadded through-the-thickness angle-interlock fabrics (TTAI) fabric reinforced composites. Their...     

新型防屈曲高强钢腹板可更换钢连梁抗震性能研究

文章率先提出一种新型防屈曲高强钢腹板可更换钢连梁(简称“新型钢连梁”)：腹板采用高强钢，可提高钢连梁的屈服抗剪强度，连梁变形减小，从而减小可更换结构整体变形，便于更换；加劲肋紧贴腹板(但不焊接)提供约束，仅与上下翼缘焊接，可减少60%以上的焊接量。其次，设计并开展了11个试件的拟静力试验，研究了加劲肋间距(规范限值dmax、0.85dmax)、腹板厚度(6mm、8mm)、腹板钢材强度(Q460、Q550)和构造形式(加劲肋与腹板贴紧或焊接)等参数对新型钢连梁抗震性能的影响。试验结果表明：试件均发生剪切破坏；满足加劲肋间距限值的新型钢连梁，滞回曲线饱满，峰值时腹板未发生鼓曲且极限转角均超过0.1rad，大于规范限值0.08rad，表现出良好的耗能和变形能力；缩小加劲肋间距、增加腹板厚度或提高腹板钢材强度，新型钢连梁刚度及承载力提高；新型钢连梁峰值承载力较传统构造试件低约5%。最后，基于试验结果建立了有限元模型并开展了分析，研究结果表明：对腹板采用Q460、Q550高强钢材的新型钢连梁，峰值承载力计算时超强系数建议取1.43(长度比为0.5～1.0)或1.39(长度比为1.0～1.6)、1.25，以期为实际工程设计提供依据。     

Spatial–Temporal Fusion Based Path Planning for Source Seeking in Wireless Sensor Network

International Journal of Wireless Information Networks - Source seeking problem has been faced in many fields, especially in search and rescue applications. We proposed a virtual structure-based...     

一种“KooN”结构的马尔可夫简并建模和简化计算的方法

IEC61508等标准提出了几种计算安全仪表系统需求时平均失效概率的方法,但是,对于具有冗余配置的复杂系统,随着组件数量的增加,系统的中间状态数量快速增长,用户难以构建马尔可夫模型,即便借助计算机来建模运算也较为耗时。提出了一种同型“K oo N”简并状态的马尔可夫建模的通用方法,首先是根据降级状态进行判断,将符合条件的状态进行简并,然后对标记为危险失效状态的概率进行计算。通过严格的理论推导,该简并状态方法可以在不损失精度的前提下简化马尔可夫建模。     

Simultaneous fractionation of multiple classes of polyphenols from honeybush tea using solid-phase extraction

The structural diversity of polyphenols and the inherent limitations of current extraction techniques pose a challenge to extract polyphenols using a simple and green method. Hence, in this study, a method was developed to simultaneously fractionate multiple classes of polyphenols by only varying ethanol-water solutions. Honeybush tea, which is rich in polyphenols, was selected as a model for this study. Solvent extraction followed by solid-phase extraction (SPE) was developed to obtain a polyphenol-rich fraction from six honeybush samples. Based on a gradient elution programme (10%, 30%, 50%, 70% and 90% (v/v) ethanol-water solution) of SPE, the Strata X cartridge showed a better recovery of most targeted polyphenols under 0.9 mL of the drying volume and 1 mL min⁻¹ of the dispensing speed. The elution programme for fractionating most polyphenols was as follows: single elution with 50% ethanol, followed by twice elution with 70% ethanol. The antioxidant capacity was used to analyse the differences among the polyphenol-rich fractions from six honeybush samples. Principal component analysis (PCA) revealed that unfermented C. genistoides (GG) has the greatest antioxidant capacity among the honeybush species studied. Additionally, mangiferin, isomangiferin and vicenin-2 were the main contributors to the antioxidant capacity in six honeybush fractions according to the correlation study.