一种复合抗氧化果蔬酵素的开发及活性研究

以富含多种天然抗氧化活性成分的果蔬为主要原料,利用具有高效脱除胆固醇能力的鼠李糖乳杆菌217-1、217-3和217-8菌株发酵制备酵素,并对酵素中总糖、多酚、黄酮等生物活性成分含量及抑制自由基氧化反应的能力进行检测。结果显示,所得酵素与未经发酵的原溶液相比,其抗氧化活性成分多酚含量提高了29.3%,黄酮含量提高了38.9%,核黄素含量提高了7.3%,原花青素含量提高了8.8%,清除自由基的抗氧化能力提高了100%。研究结果表明,复合果蔬经过发酵所得的酵素营养成分和综合抗氧化能力显著提高,在防止脂质过氧化反应,促进细胞增殖,清除体内自由基,预防皮肤早衰、延缓衰老等方面具有重要潜能。     

异形坯经压弧制成平面板坯的模拟研究

用有限元软件DEFORM-3D研究将异形板坯通过压弧方法制成平面板坯的过程,同时进行实物的物理模拟试验,再将模拟结果与试验后得到的板坯试样的平面形状进行对比分析,对比结果验证了有限元模拟方法的可行性和正确性。     

Degradation kinetics of total phenolic compounds,capsaicinoids and antioxidant activity in red pepper during hot air and infrared drying process

Degradation kinetics of total phenolic compounds, capsaicinoids and antioxidant activity in red pepper during both hot air drying and infrared drying were investigated, as well as the correlation between antioxidant compounds and antioxidant capacity was discussed in current study. The fractional conversion kinetic and first order kinetic models were proved to describe the changes of total phenolic compounds vs. drying time and moisture content, respectively. Degradation of capsaicinoids and antioxidant capacity vs. drying time and moisture content both followed fractional conversion kinetic model. Infrared drying accelerated the degradation rate of total phenolic compounds and capsaicinoids vs. drying time as compared with hot air drying at the same temperature; however, a contrary result was found that infrared drying decreased the degradation rate of both total phenolic compounds and capsaicinoids vs. moisture content. Total phenolic compounds exhibited a stronger relationship with antioxidant capacity of red pepper analysed by multiple linear regression analysis.     

Tannin fraction from Ampelopsis grossedentata leaves tea (Tengcha) as an antioxidant and α‐glucosidase inhibitory nutraceutical

Leaf of Ampelopsis grossedentata is a new resource of functional foods with healthful properties. Antioxidant and α‐glucosidase inhibitory activities of water extract (made in the style of drinking), tannin fraction (TF) and dihydromyricetin (DMY) from A. grossedentata leaves were evaluated. The main component of TF was identified as gallotannins. DPPH and ABTS radical scavenging activities and reducing power of TF were superior to those of water extract, however, inferior to those of DMY. In no PBS wash protocol of cellular antioxidant activity assay, DMY and TF exhibited similarly, while in PBS wash protocol, the value of TF was higher than that of DMY. In addition, TF possessed the highest α‐glucosidase inhibitory activities (IC₅₀ = 1.94 μg mL^?1), followed by water extract (IC₅₀ = 23.10 μg mL^?1) and DMY (IC₅₀ = 72.21 μg mL^?1). The strong α‐glucosidase inhibitory activity of TF may attribute to the binding capacity to enzymes, as confirmed by fluorescence analysis.     

光电稳定平台伺服系统动力学建模与参数辨识

针对光电稳定平台伺服系统模型参数辨识问题,提出了线性和非线性模型参数分离辨识方法。在线性模型参数辨识过程中,利用差动逆M序列信号作为输入,相应的响应信号作为输出,并应用最小二乘方法辨识线性离散模型参数,从而降低非线性因素的影响。在非线性模型参数辨识过程中,以LuGre摩擦模型为基础,针对摩擦和不平衡质量相互耦合的问题,提出了考虑不平衡质量的LuGre模型静态参数辨识方法;然后,利用电流信号作为摩擦力测量值,对LuGre模型动态参数进行辨识,得到包含不平衡质量和动态摩擦的系统非线性部分模型参数。构建了单轴光电稳定平台实验系统,利用本文提出的方法对实验系统动力学模型参数进行了辨识。结果表明:质量不平衡力矩的辨识值为0.183N·m,略高于理论值0.18N·m,满足辨识精度要求。实验证实提出的辨识方法可以实现对模型线性与非线性参数的有效辨识。     

LG气田三维应急地理信息系统的建设

中国石油西南油气田公司作业区较为分散,区域内人口密度大,生产场站远离公司机关。因此各级管理部门快速了解突发事件现场情况,正确判断事态发展,科学利用周边应急资源,对保障油气田安全平稳生产意义十分重大。为此,开展了LG气田试采工程三维应急地理信息系统建设。2009年11月利用该系统在LG气田开展了大型多方应急演练。演练结果表明,该系统按建设方案实现了现场应急监控、数据传输、应急方案制订、疏散线路规划、应急力量整合以及应急资源调配等功能。该系统是LG气田应急体系的重要组成部分,主要针对气田突发事件应急反应和日常应急事务管理而开发研制,除具备区域地理信息外,还包含有环境敏感区数据库、应急救援力量数据库和事故后果模拟模型库等,具有预测突发事件后果和在人机交互情况下模拟处理突发事故等功能。该系统已正式投入使用。     

大型风电机组塔筒应力监测点的选取与预警

针对大型风电机组塔筒应力监测缺失的情况,提出基于ANSYS软件应力点的选取和person相关系数法与灰色神经网络相结合的塔筒应力预警方法。通过软件分析和现场实验,研究风电数据和塔筒应力的关系并进行塔筒预测,并首次应用到风电机组塔筒监测中。通过实例分析验证,结果表明,该方法能够有效地进行塔筒应力监测,为风电机组塔筒的检测提供依据。     

辛烯基琥珀酸淀粉酯纳米颗粒稳定Pickering乳液及其乳化性分析

采用醇沉法制备辛烯基琥珀酸玉米淀粉酯纳米颗粒,分别以去离子水和玉米油为水相和油相,制备Pickering乳液。通过考察乳液乳化指数、乳液粒径和乳液液滴微观结构分析辛烯基琥珀酸淀粉酯取代度、淀粉酯纳米颗粒浓度和油水体积比等因素对乳液乳化性的影响。结果表明,淀粉酯纳米颗粒能够很好地稳定Pickering乳液,乳液乳化指数随着淀粉酯取代度、淀粉酯纳米颗粒浓度、油水体积比的增加而增大;乳液粒径随淀粉酯纳米颗粒取代度、淀粉酯纳米颗粒浓度的增大呈下降趋势,当油水体积比增大时,乳液粒径呈上升趋势。     

圆形封闭水箱非稳态数值模拟

采用数值方法对圆形封闭水箱内放置两根加热管的二维流动传热进行了非稳态数值模拟,探讨了Ra数从104到107四种情况和封闭水箱的加热管不同摆放位置下的流动和换热;对流场和温度场进行了分析,讨论了不同情况下加热管平均努赛尔数(Nuavg)的变化情况。数值模拟结果表明,随着Ra数增大水箱内的流动表现出了很大变化,决定了传热是导热或者是对流;两个水平加热管在水箱存在最佳的放置距离,这样可以使自然对流情况下的换热达到最好。