Tempering–preservation treatment inactivated lipase in wheat bran and retained phenolic compounds

Wheat bran is rich in functional ingredients, but the high level of lipase limits its applications. Tempering–preservation treatment (at 70–90 °C with moisture of 20%–40% for 1–4 h) was exploited for stabilising wheat bran and its effect on polyphenols was investigated. The results showed that more lipase was inactivated at higher tempering moisture, temperature and longer time. The optimum condition for inactivation of wheat bran lipase was 30% moisture and 90 °C for 4 h. The inactivation rate reached 93.8% with a residual enzyme activity of 0.264 U g⁻¹. Under the optimum condition, the sum of free phenolic acids rose from 25.4 to 55.8 µg g⁻¹. As for bound phenolic acids, there was a slight increase of hydroxybenzoic acid derivatives but a slight decrease of hydroxycinnamic acid derivatives. The total contents of phenolic acids before and after stabilisation were not significantly different. This study showed the possibility of using tempering–preservation as an efficient method for inactivation of wheat bran lipase while maintaining its phenolic compounds, which could be used in the production of whole wheat flour.     

PWR堆芯燃料组件非线性梁模型研究

为描述燃料组件的非线性特性，采用有限元方法建立燃料组件横向梁模型，并引入迟滞模型，用于模拟燃料组件横向变形时的非线性效应。计算结果表明:该非线性梁模型能够更准确地获得组件的弯曲变形和受力，有助于开展燃料组件事故分析。      

求解二维结构-声耦合问题的一种直接方法

本文基于传递矩阵法(TMM)和虚拟边界元法(VBEM)，提出了一种求解在谐激励作用下二维结构-声耦合问题的直接法。文中对任意形状的二维弹性环建立了一阶非齐次运动微分方程组，便于用齐次扩容精细积分法求解，对于含有任意形状孔穴的无穷域流体介质的Helmholtz外问题，采用复数形式的Burton-Miller型组合层势法建立了虚拟边界元方程，保证了声压在全波数域内存在唯一解。根据叠加原理并结合最小二乘法，提出了一种耦合方程的直接解法，由于该方法不存在迭代过程，因而具有较高的计算精度和效率。文中给出了二个典型弹性环在集中谐激励力作用下声辐射算例，计算结果表明本文方法较通常采用的混合FE／BE法更为有效。     

激光二极管线阵光束变换研究

推导出激光二极管线阵光束通过透镜系统的光强分布表达式，分析了出射光束的传输特性，设计一种凹柱透镜的光束变换系统得到一维均匀光强分布。此外，给出扩展角宽度的计算公式。     

Postbuckling analysis of plates on an elastic foundation by the boundary element method

The postbuckling behavior of plates on an elastic foundation is studied by using the boundary element method (BEM). A new fundamental solution of lateral deflection is derived through the resolution theory of a differential operator, and a set of boundary element formulae in incremental form is presented. By using these formulae, the BEM solution procedure becomes relatively simple. The results of a number of numerical examples are compared with existing solutions and good agreement is observed. It shows that the proposed method is effective for solving the postbuckling problems of plates with arbitrary shape and various boundary conditions.     

准分子激光器异步感应密封传动技术

一种新型准分子激光器循环系统中的密封传动技术，具有可耐高气压，不失耦，不使用昂贵强磁材料，结构简单等优点，虽有涡流损失过大之不足，但能很好地适用于小功率下运行。     

圆锥形零件冲压变形与成形载荷的分析

由于悬空侧壁部分的变形状态是圆锥形零件成形的关键，而径向拉应力是实现悬空部分成形的必要条件，同时也是该部分冲压成形成败的关键为此，经力学分析得出了侧壁部分径向拉应力的解析式和造成圆锥形零件破裂的最大径向拉应力的计算式。同时分析了圆锥形零件的成形载荷。     

肟交换法制备乙醛肟工艺的研究

肟交换法是一种制备乙醛肟的新兴工艺,但反应过程存在乙醛肟易被空气氧化等问题,且反应液中存在多组共沸物,分离提纯得到高纯度的乙醛肟较为困难。以丁酮肟为原料,通过向反应器内充入0.2 MPa的氮气,有效避免了乙醛肟氧化与原料乙醛、丁酮肟的挥发,乙醛肟反应选择性达96.12%。开发了产物的提纯工艺,通过Aspen Plus模拟,初步确定减压精馏分离反应液的基本流程,考察了压力、塔板数、回流比、进料位置等操作参数对分离过程的影响。在此基础上,依据模拟确定的操作参数进行实验,确定最优分离提纯工艺,得到纯度为95.33%的乙醛肟产品,收率可达94.31%。本研究可为肟交换法制备乙醛肟的工业化提供一定的指导。     

基于NSGA-Ⅱ算法的互补能源接入方案优化配置

构建以电力为主体,融合热、气等不同形式能源,在生产、消费多个环节优势互补的多能源系统,是提升能源利用效率,促进能源清洁发展,构建能源互联网的关键.首先,依据风、光等分布式能源稳定模型,构建智慧城市多能互补系统架构;然后综合考虑投资商、电力公司、用电客户等能源主体利益,以系统潮流、接入互补能源的节点电压、装机容量等为条件,建立智慧城市多能互补系统规划模型;最后,引入改进的遗传进化算法,确定模型的寻优流程,对多能互补系统能源网络接入能源的节点位置与装机容量进行优化求解.结果表明,对多能互补系统合理规划,有助于智慧城市能源供应向清洁、可持续化方向发展.     

低熔点Cu-P基中间合金及其变质效果

利用差示扫描量热仪(DSC)、扫描电子显微镜(SEM)和金相显微镜等手段对Cu-P基中间合金进行了研究。结果表明，在二元共晶Cu-P中间合金中加入一定量的Sn可制成低熔点的Cu-16Sn-8P中间合金；在此基础上研制出一种熔点为630℃左右的低熔点的多元Cu-P基中间合金。与Cu-P中间合金相比，该低熔点多元Cu-P基中间合金对过共晶AI-24Si合金具有更好的变质效果。同时，该中间合金对ZL109合金也具有良好的变质效果。