基于模糊自学习的交流直线伺服系统滑模变结构控制

针对直接驱动直线式交流伺服系统,提出了一种基于模糊自学习的滑模变结构控制方案。在常规的滑模控制中引入模糊自学习方法,在不影响滑模控制系统完全鲁棒性的情况下,有效地削弱滑模切换控制所产生的抖振。仿真结果表明该方案对系统参数变化和负载扰动具有很强的鲁棒性,抖振得到了明显的抑制。系统具有良好的动、静态性能。     

多声源数据采集系统仿真及实验平台设计

本文设计了多声源数据采集系统仿真及实验平台,仿真系统利用VB编程技术具有可视化的优点。实验平台利用PC机及外扩声卡可高效采集数据,即节约了硬件成本,又完成了多个声源的同时采集,提高了工作效率。最后给出了声源及麦克风阵列的设计原则。     

一种相位延迟型偏振控制器的误差分析与研究

文章研究了45°-0°-45°相位延迟型偏振控制器的控制算法,对相位延迟量引入的误差进行了分析,并通过仿真得到输出偏振态的方位角误差和椭率角误差与延迟量误差之间的关系.结果表明,延迟量误差对该偏振控制器输出偏振态的椭率角误差的影响小于对方位角误差的影响.还分析了入射光波长误差导致的延迟量误差对输出偏振态精度的影响,仿真结果表明,45°-0°-45°相位延迟型偏振控制器是对波长敏感的.     

Optimization of microwave-assisted extraction of anthocyanins from mulberry and identification of anthocyanins in extract using HPLC-ESI-MS

Anthocyanins are naturally occurring compounds that impart color to fruits, vegetables, and plants. This study aims to optimize the microwave-assisted extraction (MAE) conditions of anthocyanins from mulberry (M. atropurpurea Roxb.) using response surface methodology (RSM). A Box-Behnken experiment was employed in this regard. Methanol concentration, microwave power, and extraction time were chosen as independent variables. The optimized conditions of MAE were as follows: 59.6% acidified methanol, 425 W power, 25 (v/w) liquid-to-solid ratio, and 132 s time. Under these conditions, 54.72 mg anthocyanins were obtained from 1.0 g mulberry powder. Furthermore, 8 anthocyanins were identified by high-performance liquid chromatography-electrospray ionization-mass spectrometry (HPLC-ESI-MS) in mulberry extract. The results showed that cyanidin-3-glucoside and cyanidin-3-rutinoside are the major anthocyanins in mulberry. In addition, in comparison with conventional extraction, MAE is more rapid and efficient for extracting anthocyanins from mulberry.     

Antimicrobial activity and mechanism of PLA/TP composite nanofibrous films

Electrospinning is conducted with polylactic acid (PLA) and tea polypheno (TP) to obtain PLA/TP composite nanofibrous films with high antimicrobial activity. An investigation of the composition, antimicrobial activity, and mechanism of these composite nanofibrous films was conducted by using infrared spectroscopy (FT-IR), inhibition zone method, fluorescence activated cell sorter (FACS), and transmission electron microscope (TEM). IR spectra results showed that TP and PLA composited well through valence bonds in PLA/TP composite nanofibrous films. Ranges of the inhibition zone for the growth of Escherichia coli (E. coli) and Staphylococcus (Staphylococcus aureus) were 3.67 and 3.71?cm in pure PLA nanofibrous films, but 5.17 and 5.67?cm in PLA/TP composite nanofibrous films, respectively. Results indicated that the antimicrobial activity of PLA/TP composite nanofibrous films were much higher than that of pure PLA nanofibrous films. Meanwhile, the antimicrobial activity against S. aureus was also slightly higher than E. coli. FACS results showed that the positive rate of PLA/TP composite nanofiber films was greater than that of pure PLA nanofibrous films, increasing from 1.45 and 0.78% to 9.26 and 6.47% against S. aureus and E. coli, respectively. The result of TEM indicated that PLA/TP composite nanofibrous films led to the death of bacteria by destroying the integrity of cell membrane.     

抗菌剂在抗菌纸中的应用研究

从无机抗菌剂、有机抗菌剂、天然抗菌剂三方面阐述了抗菌剂在抗菌纸方面的应用,指出使用单一抗菌剂往往不能满足抗菌纸的某种要求,抗菌剂的使用向着改性和混合联用的方向发展。为了满足抗菌剂在抗菌纸中应用的需求,需要深入了解其所涉及的学科和领域,改进生产工艺,使其更适合大规模生产的需要,加大产、学、研合作的力度,完善相关的法规和规定。     

（2＋1）维Broer-Kaup-Kupershmidt方程的行波解及其分岔

利用平面动力系统的分岔理论研究了（2＋1）维Broer-Kaup-Kupershmidt （BKK ）方程。给出了方程在不同的参数区域所对应的所有可能存在的行波解,并得到了方程在一些特殊的参数条件下的显式精确孤立波解及周期波解的表达式。     

煤基活性炭的制备及CH_4/H_2分离性能

以神东煤为原料,KOH为活化剂制备高比表面积活性炭,分别考察碱煤比、活化温度和活化时间对活性炭孔结构的影响,并用于CH4和H2的吸附与分离.结果发现,制得活性炭的比表面积和孔容随碱煤比和活化时间的增加分别呈增加和先增加后减小的趋势,但比表面积受活化温度影响不大,孔容随活化温度升高而增加;适合于CH4和H2分离的活性炭的最佳制备条件为:碱煤比为5,活化温度800℃,活化时间为90min.     

外墙饰面砖安全粘贴技术条件研究

通过对不同外墙饰面砖、同样水泥砂浆评估陶瓷砖自身特性以及环境条件对粘结强度的影响。结果表明,陶瓷砖自身特性,如吸水率、背纹形状与分布、背纹深度、表面粗糙度对粘结强影响较小,而环境条件对粘结强度影响最大。在14d热老化、冻融循环(-18±5)℃6h浸(20±5)℃6h、7d标准状态三种养护条件下,利用万能测试机对16种不同的试样砖进行粘结强度的测试,试验结果发现,标准状态下,试样的粘结强度最大;冻融循环后,试样的粘结强度最小。     

激光自动跟踪式引伸计的优化设计

通过将一类LD结构光作为扫描光线,结合激光自动跟踪技术对一种非接触式引伸计的机械组成与光路结构部分进行了优化设计.通过构建系统的数学模型和公式推导,分析了各组成部分之间的关系,通过仿真,确定了各参数的取值范围与适用条件.由实验验证了所设计的系统优化方案的正确性和可行性.实验结果表明,所设计的引伸计具有满足试件拉伸过程的全量程测量、测量结果精度高、结构方面易于实现等优点.