Optimization of Extraction of Antioxidants from Turmeric(Curcuma longa L.) Using Response Surface Methodology

Turmeric is a spice widely used to enhance the taste and color of certain meats. We investigated the antioxidant capacities of turmeric ethanol soaking extracts by utilizing the scavenging properties of hydroxyl radical and 1,1-diphenyl-2-picrylhydrazyl(DPPH) free radical. The results showed that the optimum extraction parameters were: extraction time 4 h, sample-solvent ratio 1:84.12, solvent 72.34% ethanol solution, and water bath temperature 81.3 ℃. The optimum ethanol soaking extraction parameters were: extraction time 4 h, sample-solvent ratio 1:90.74, solvent 80.46% ethanol solution, water bath temperature 88.2 ℃. With these parameters, the hydroxyl radical scavenging rate and the DPPH free radical clearance of crude extracts from turmeric can reach about 93.78% and 40.69%, respectively. These results indicate that ethanol soaking extraction may be a useful method for extracting antioxidants from turmeric.     

Nuclear Norm Subspace System Identification and Its Application on a Stochastic Model of Plague

The discrete-time model of plague is deduced by zero-order holder based on the continuoustime model. Due to the existence of stochastic disturbances, the stochastic model is given corresponding to the discrete-time model. The state estimation and noise reduction of the stochastic model are achieved by designing Kalman filter. Nuclear norm minimization is to structure the low-rank matrix approximation instead of the singular value decomposition in the process of subspace system identification. According to the plague data from the World Health Organization, the system matrices and noise intensity of the model are identified. Simulations are carried out to show the higher approximation capability of the proposed method.     

外国人文艺术素质教育探析

人文艺术素质教育在全球范围内广泛开展并不断的深入。本文对外国人文艺术素质教育进行探析，希望能总结国外经验对我们搞人文艺术素质教育有所启示。     

基于STL文件的有限元模拟模具自动生成技术

针对板料成型模拟技术，在分析三维STL文件格式数据结构的基础上，提出了对实体数据模型进行自动诊断与修复的原则和方法，并自动生成具有三角形网格的冲压模具，减轻了模具网格剖分的工作量，开发了适应性强的程序，通过实际应用证明了程序的实用性。     

多年调节水库补偿调节联合运行模型及人机对话算法

结合多年调节水库特点,本文建立了多年调节水库补偿调节联合运行模型,提出了一种基于等出力补偿调节计算、决策者参与的人机对话算法,通过实例计算表明,该算法具有计算速度快、占用内存少、决策者参与计算等优点,是解决多年调节水库联合运行计算的有效途径,具有重要推广、实用价值。     

织机送经机构的系统辨识与计算机仿真

用系统辨识的方法建立了Picanol织机送经机构的数学模型,在计算机仿真的基础上分析了该送经机构的动态特性,提出了改进的途径和措施。     

混凝土施工中裂缝产生原因分析及防治

裂缝在施工中常见的为温度裂缝、收缩裂缝、沉陷裂缝等，依据混凝土特性及施工工艺方法加以防治的技术要求必须十分规范，施工操作必须严格。     

Optimization of extraction of antioxidants from turmeric (<Emphasis Type="Italic">Curcuma longa</Emphasis> L.) using response surface methodology

Turmeric is a spice widely used to enhance the taste and color of certain meats. We investigated the antioxidant capacities of turmeric ethanol soaking extracts by utilizing the scavenging properties of hydroxyl radical and 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical. The results showed that the optimum extraction parameters were: extraction time 4 h, sample-solvent ratio 1:84.12, solvent 72.34% ethanol solution, and water bath temperature 81.3 ℃. The optimum ethanol soaking extraction parameters were: extraction time 4 h, sample-solvent ratio 1:90.74, solvent 80.46% ethanol solution, water bath temperature 88.2 ℃. With these parameters, the hydroxyl radical scavenging rate and the DPPH free radical clearance of crude extracts from turmeric can reach about 93.78% and 40.69%, respectively. These results indicate that ethanol soaking extraction may be a useful method for extracting antioxidants from turmeric.     

EMI滤波器插入损耗的理论计算与铁基纳米晶材料的应用

采用网络参数法,导出了单、双级电源滤波器共模和差模插入损耗的理论计算公式。计算与测试相比,在低频段较为吻合。另外,首次将一种新材料——铁基纳米晶软磁材料用于EMI滤波器,提高了滤波器低频段的共模插入损耗。     

拖拉机变速箱异常噪声的逆频谱诊断与排除

本文采用自功率谱、逆频谱方法对拖拉机变速箱异常噪声源进行了诊断,找出了产生异常噪声的根源。在此基础上,更换了产生异常噪声的齿轮,使该变速箱的噪声降低了0.2～4dB(A)。