基于BP-GA的大锻件过渡区宏观成形性能优化

针对铝合金大型锻件局部加载成形工艺下过渡区筋部充填不满的问题,借助于BP神经网络和GA遗传算法与数值模拟技术相结合的策略对锻件的局部加载成形工艺参数进行了研究。以锻件过渡区填充性作为质量评价目标,建立了坯料温度、压力机加载速度、第1道次压下量、进给量与质量指标之间的关系模型,利用遗传算法求解得到了合理的工艺参数:坯料温度为435℃,压力机加载速度为5 mm·s-1,第1道次压下量为18 mm,进给量为1165 mm,并将得到的工艺参数进行再模拟,并应用于生产试制,生产后的锻件筋部过渡区充填完整,对比模拟结果,表明所提出的策略能有效对大型锻件局部加载成形过渡区充填问题进行控制。     

Plastic coupled instabilities of I-shaped steel beams

The paper presents the case of plastic instability of I-shaped beams where the rotation capacity is a very important characteristic in order to assure the required ductility in plastic or seismic design. The failure of such beams can be due to the local plastic plate buckling of compression flange and local plate buckling of the web in flexural compression, produced in-plane or out-of-plane. In the same time the failure can occurs by coupling of these two local buckling modes. In order to study the plastic buckling of beams and to determine the available rotation capacity which is required by the plastic or seismic design, the collapse plastic mechanism theory was developed and a specialized computer program DUCTROT-M was elaborated. The parametrical analysis reveals the paramount importance of the web to thickness ratio and furthermore the sensitivity in out-of-plane buckling of the European hot-rolled sections.     

尿素工艺DCS控制系统增容设想

在现有DCS控制系统的基础上，进行了初步增容改造的设想，对CO2压缩机和合成系统增加了部分新的控制手段和方法。     

钻孔灌注桩桩底压浆工艺及其应用

通过实例对钻孔灌注桩桩底压浆施工工艺进行分析，阐述应用的价值和效果。     

Ascorbic acid contribution to ORAC values in berry extracts: An evaluation by the ORAC-pyrogallol red methodology

An oxygen radical absorbance capacity (ORAC) method based on pyrogallol red bleaching (ORAC-PGR) was used to evaluate the scavenging activity of berry extracts (blackberry, blueberry, and raspberry). Among berry extracts, only raspberry protected pyrogallol red through a clear induction time, related exclusively to ascorbic acid. The lag time allowed an estimation of the ascorbic acid concentration and its contribution to the total ORAC value, estimating that 66% of the ORAC-PGR value of raspberry is related to ascorbic acid. Also, from the induction time, an ascorbic acid concentration of 36 mg per 100 g of fresh weight was estimated for raspberry samples. The ORAC-PGR procedure could be considered as a fast and specific methodology for an estimation of ascorbic acid concentrations in complex samples.     

聚丙烯纤维再生混凝土柱受压性能的模拟分析

对聚丙烯纤维再生混凝土柱进行了研究,从柱的受压性能方面进行了论述,并采用ABAQUS有限元模拟的方法,对极限承载力和荷载—挠度曲线进行了分析,得到了柱的承载力变化和荷载—挠度关系。     

双回路直线型钢管角钢输电塔静动力分析

采用有限元分析软件ANSYS对500 kV双回路直线型圆管角钢输电塔进行了静动力分析,研究方法及主要结论如下：运用静风极限承载力的分析方法,计算出铁塔在各个方向的极限承载力较为接近,通过塔体动力特性的分析,变刚度处设计应予以重视。     

Salt in food processing; usage and reduction: a review

Salt is one of the most widely used additives in food industries because of its low cost and varied properties. It has a preservative and antimicrobial effect as a direct consequence of the capacity of sodium chloride to reduce water activity values. In addition, sodium chloride is a flavour enhancer as a consequence of its effect on different biochemical mechanisms. It also has flavour enhancing effects from reducing or enhancing the enzymatic activity of some enzymes responsible for the development of different organoleptic parameters. Trends in sodium chloride use in food industries point to salt replacement or reduction by means of the use of sodium chloride substitutes such as KCl or phosphates; flavour enhancers and the optimisation of the physical form of salt. This trend has arisen as a result of the greater awareness of the negative effects of excess dietary intake of sodium, which has been linked to hypertension and consequently an increased risk of cardiovascular disease. The average total daily sodium intake per individual in developed countries is 4–5 g of Na, which is up to 25 times greater than the minimum adult requirement.     

超级电容电池容量自动检测系统的研究

超级电容电池又叫双电层电容器,是一种新型储能装置,目前国内外对于超级电容电池容量的检测系统自动化程度不高,多数工作由人工控制完成。本文总结了相关蓄电池的自动检测系统,在此基础上提出了适合于超级电容电池的自动检测装置,并通过此装置检测出超级电容电池的常温容量,低温容量以及高倍率放电能力,为今后超级电容电池的自动化检测提供一套可行方案。