响应面法优化辣椒中辣椒素微波提取工艺的研究

以微波萃取法从干辣椒中提取了辣椒素,采用响应面分析法对辣椒素的提取工艺条件进行了优化。结果表明,最佳的提取工艺条件是：浓度为65％乙醇溶液,辣椒粉与乙醇溶液比为1：10,温度90℃,时间3．5min,功率400w。在最佳的提取工艺条件下,辣椒素的提取率最高可达5‰。     

单峰过载对工业纯钛CT试样裂纹闭合效应的影响

基于数字图像相关技术,使用非线性迭代法拟合工业纯钛CT试样表面位移场,获得了过载前、过载时、过载后循环的裂纹尖端位置随载荷的变化规律.使用数字图像相关技术获取裂纹张开位移,通过间接法测量裂纹张开力,进而研究过载对裂纹闭合效应的影响.对比过载前一循环与过载循环在卸载状态下裂纹尖端附近区域的应变场,结合裂纹尖端位置随载荷的变化规律及相对应循环的裂纹张开力,分析可知:过载在裂纹尖端附近区域产生较大塑性变形,即使卸载后仍在较大程度上得到保留,从而使裂纹闭合效应减弱,导致过载后裂纹尖端位置随载荷的变化规律与过载前明显不同,且力-位移曲线也未出现显著的转折点.     

Analysis of external noise spectrum of high-speed railway

A schematic to make the spectra of the exterior noise of high speed railway was put forward. The exterior noise spectrum was defined based on the characteristics of the high-speed train exterior noise. Its characteristics considered here include identifying the exterior main sources and their locations, their frequency components including the Doppler effect due to the noise sources moving at high speed, the sound field intensity around the train in high-speed operation, the sound radiation path out of the train, and the pressure level and frequency components of the noise at the measuring points specified by the International Organization for Standardization（ISO）. The characteristics of the high-speed train exterior noise of the high speed railways in operation were introduced. The advanced measuring systems and their principles for clearly indentifying the exterior noise sources were discussed in detail. Based on the concerned noise results measured at sites, a prediction model was developed to calculate the sound level and the characteristics of the exterior noise at any point where it is difficult to measure and to help to make the exterior noise spectrums. This model was also verified with the test results. The verification shows that there is a good agreement between the theoretical and experimental results.     

新一代中国高速铁路动车组面临的技术挑战与策略研究

基于新一代中国高速列车(动车组)关键技术的研究发展趋势和策略问题进行详细讨论和技术展望。主要内容包括:首先,介绍国际先进轨道车辆制造商在其新一代车辆开发过程中采用的先进设计技术和理念,分层次研究其各自的核心技术特点和未来其可能的技术发展趋势。其次,在国内外文献研究的基础上,结合中国高速铁路车辆发展的自身特点和实际情况,针对具体的牵引传动技术、转向架技术、车体设计技术等可能面临的核心技术难题,提出一些分析建议。最后,在综合考虑轨道车辆造型发展趋势及设计原则的基础上,根据集成设计的理论与多学科优化设计方法,针对新一代中国高速铁路动车组可能面临的重大技术挑战与策略和改进措施的研究提出一些明确的建议。总之,通过本文的初步研究,希望可以对我国高速列车未来的发展方向和趋势提出一些有益的建议。