Due to three free hydroxyl groups, hydroxytyrosol (HT) presents strong bioactivity and has broad food and drug application prospects. However, there is no good separation and purification technology. In this study, separation and purification technology of HT from the ethyl acetate extraction of enzymatic hydrolysate from olive leaf (EEEH) was investigated with macroporous adsorption resin (MAR) and high-speed counter-current chromatography (HSCCC) and the separation factors were optimized. First, the adsorption properties of eight MARs (AB-8, S-8, D-101, X-5, XAD-1, XAD-5, NKA-Ⅱ, H-103) for HT enrichment were studied. The results showed that H-103 macroporous resin was adsorbent, sample concentration was 1.5 mg/mL, eluent was 30 % ethanol solution, sample loading rate was 3.0 BV/h, elution velocity was 2.0 BV/h, and HT purity of EEEH was increased from 10.23 % to 40.78 %. Then, solvent systems were examined according to partition coefficients of target component and petroleum ether: ethyl acetate: methanol: water (4:6:4:6, v/v) system was chosen. The critical experimental parameters of HSCCC were optimized as following: revolution speed was 1200 rpm and flow rate was 3 mL/min. The HT purity of macroporous resin purified EEEH was increased from 40.78 % to 85.7 %. Therefore, MAR-HSCCC combined technology could be a very effective approach to separate and purify HT from EEEH.

The fast growing demand for constant updating of information technology has made its side effect of electronic interfere and radiation a prominently serious problem. Compared with other types of MA(microwave absorption) absorbers, biomass-based absorbers are a highly promising sort, due to their low weight, possession of unique intrinsic structures, and low cost, which is essential for practical use. However, owing to their exorbitant relative complex permittivity, the undesirable impedance mismatching has often been obtained, which typically leads to both limited MA capabilities and a narrow effective absorption band. Hence, various strategies such as activation processes or doping of magnetic materials have been employed to boost the MA performances of biomass based materials, and these further modifications will inevitably add cost, making the advantage of low cost for biomass at least compromised or even lost. This research employs the silky pappi of the fruit of Ceiba speciosa (A. St.-Hil.) to furnish biomass-derived absorbers through one-step direct calcination. Together with high aspect ratio, its unique tubular hollow structures can act as resonators, which allows for multiple reflections and scatterings, highly facilitating the dissipation of undesirable energies. The results show that the sample annealed at 700 degrees C (Cs-700) has effective absorption bandwidth as wide as 9.3 GHz (8.7-18 GHz) at the thickness of 3.36 mm under the ultra low filler sample ratio of only 7%. Moreover Cs-700 presents broadband absorption at all the five tested thicknesses with the narrowest band of 6.2 GHz. Furthermore, when calcination temperature was risen to 800 degrees C, much inferior effective bandwidth, the maximum of which is only 5.8 GHz, has been found. Thus, high aspect ratio, unique hollow tubular structures, as well as a subtle balance of between attenuating abilities and impedance matching account for the exceptional MA performance of Cs-700. We believe these findings open a window for the future structure design of biomass based MA materials.

受剪承载力是开展钢筋再生混凝土结构设计和修复加固所依据的重要性能指标之一,发展其计算理论具有较强的科学与实践意义.然而受制于有限的试验数据及再生混凝土材性离散较大等原因,现行规范在预估此类构件受剪承载力时,往往简单对混凝土强度进行折减,套用普通钢筋混凝土构件的计算公式.该法通常存在精度低和稳定性差等问题.为此,首先尝试建立包含206根再生混凝土无腹筋梁的抗剪试验数据库,用以评估现存规范与经验计算公式的准确性及可靠性;紧接着,选定预测效果较好的ACI318-2014规范和学者Zsutty建议公式为先验模型,基于贝叶斯统计理论对先验模型和试验信息进行统计推断,构建起无箍筋钢筋再生混凝土梁受剪承载力计算概率模型;随后通过未知参数的筛选剔除,修正得到后验模型.研究结果表明:贝叶斯方法充分融合了先验模型的完备性及大量试验数据的准确性,能更精准地预测再生混凝土无腹筋梁的受剪强度.

为分析和评价城市轨道交通应急能力的影响因素,构建了城市轨道交通应急能力影响因素三级指标.提出了一种集成DEMATEL-ISM-TOPSIS(决策试验分析与评价-解释结构模型-优劣解距离)法用于分析与评价,厘清了评价因子的层级关系和主从逻辑关系以探究各指标的属性.通过原因度和中心度得分分析了城市轨道交通应急能力的关键因素和核心影响因素,构建了应急能力因素象限分布图;通过ISM分析了表层和深层次的影响因素,基于各评价因子的逼近理想解对指标客观赋权;最后对3条轨道交通线路打分评价,表明了评价指标的适用性和研究方法的科学性.

为了研究桩板墙施工振动对邻近建筑物的影响,依托于某道路连接线工程,对桩板墙施工振动的传递规律进行了现场监测,获得了距离振源不同位置处的速度时程和速度频谱,并对不同位置处3个方向振动频率和速度峰值进行了统计分析.结果表明:桩板墙施工引起的邻近建筑物振动表现为整体振动,但以水平振动为主;随着测点远离振源,振动呈衰减趋势,符合振动波传递规律.此外,还给出邻近建筑物振动实测资料的评价分析结果,可为类似工程的施工提供一定的参考和借鉴.

研究背景 随着信息化技术的不断发展,传统课程领域正在发生巨大的变革.在这场变革中,"一纸书本、三尺讲台"的课堂形式受到电子书,电子书包、网络课程、虚拟交互课程、远程教学等新的课程教学形态的冲击.随着"互联网+"、"云计算"等技术在信息技术领域不断成熟,借助笔记本电脑、平板电脑、智能手机等终端设备在"云端"授课、互动、游戏、实验、作业、考试的"云课程"逐渐进入人们的视野 .

研究背景 随着我国各个城市城市化水平的不断推进,各个地区城市轨道交通的建设及运营得到了快速发展.轨道交通成为输送客流的最主要措施,已成为城市交通客流输送系统中的骨干.东莞作为修建轨道交通的后起之秀,也面临着如何为大规模乘客出行提供方便、快捷、舒适的交通服务的巨大挑战,而东莞连接两大都市广州和深圳的特殊地理位置,使得高客运服务质量成为当前运营单位解决此问题的核心措施.

逆向可变车道作为一种可极大提高道路通行能力的有效交通措施,被应用于交通的各个领域.在我国,逆向可变车道已被很多城市用于处理早高峰及晚高峰时段的交通拥堵.但关于逆向可变车道在应急疏散条件下的相关研究相对比较匮乏.因此,本论文在应急疏散条件下,对逆向可变车道做了相应的定义;并对逆向可变车道的应用领域进行了归纳研究.