梁结构振动支承约束反力控制

支承或连接构件对梁结构的动力学性能有至关重要影响,必须保证其在振动过程中不发生破坏或者失效。通过合理设计和布局附加弹性支承可以实现对这些重要连接构件所承受约束反力的控制。应用微分变换法推导含附加支承的梁结构支承约束反力及其对于附加支承位置和刚度的灵敏度表达式,并通过优化设计附加支承位置和刚度实现具有弹性约束端的简支梁结构各支承约束反力的平衡,可提高结构的动力学性能。     

Simultaneous fractionation of multiple classes of polyphenols from honeybush tea using solid-phase extraction

The structural diversity of polyphenols and the inherent limitations of current extraction techniques pose a challenge to extract polyphenols using a simple and green method. Hence, in this study, a method was developed to simultaneously fractionate multiple classes of polyphenols by only varying ethanol-water solutions. Honeybush tea, which is rich in polyphenols, was selected as a model for this study. Solvent extraction followed by solid-phase extraction (SPE) was developed to obtain a polyphenol-rich fraction from six honeybush samples. Based on a gradient elution programme (10%, 30%, 50%, 70% and 90% (v/v) ethanol-water solution) of SPE, the Strata X cartridge showed a better recovery of most targeted polyphenols under 0.9 mL of the drying volume and 1 mL min⁻¹ of the dispensing speed. The elution programme for fractionating most polyphenols was as follows: single elution with 50% ethanol, followed by twice elution with 70% ethanol. The antioxidant capacity was used to analyse the differences among the polyphenol-rich fractions from six honeybush samples. Principal component analysis (PCA) revealed that unfermented C. genistoides (GG) has the greatest antioxidant capacity among the honeybush species studied. Additionally, mangiferin, isomangiferin and vicenin-2 were the main contributors to the antioxidant capacity in six honeybush fractions according to the correlation study.     

Dual effect synergistically triggered Ce:(Y,Tb)3(Al,Mn)5O12 transparent ceramics enabling a high color-rendering index and excellent thermal stability for white LEDs

Ce:Y₃Al₅O₁₂ transparent ceramics (TCs) with appropriate emission light proportion and high thermal stability are significant to construct white light emitting diode devices with excellent chromaticity parameters. In this work, strategies of controlling crystal-field splitting around Ce³⁺ ion and doping orange-red emitting ion, were adopted to fabricate Ce:(Y,Tb)₃(Al,Mn)₅O₁₂ TCs via vacuum sintering technique. Notably, 85.4 % of the room-temperature luminescence intensity of the TC was retained at 150 °C, and the color rendering index was as high as 79.8. Furthermore, a 12 nm red shift and a 16.2 % increase of full width at half maximum were achieved owing to the synergistic effects of Tb³⁺ and Mn²⁺ ions. By combining TCs with a 460 nm blue chip, a warm white light with a low correlated color temperature of 4155 K was acquired. Meanwhile, the action mechanism of Tb³⁺ ion and the energy transfer between Ce³⁺ and Mn²⁺ ions were verified in prepared TCs.     

中药桂枝总黄酮的提取工艺研究

优化桂枝总黄酮的提取工艺，建立桂枝的提取和含量测定方法。通过单因素试验，考察提取方法、提取溶剂浓度、提取体积、提取时间对药材总黄酮含量的影响，采用正交试验，优化提取工艺条件，筛选出桂枝总黄酮的最佳提取工艺。总黄酮最佳提取工艺为75%乙醇、料液比1:40、回流提取时间60 min。该方法能有效测定桂枝药材总黄酮的含量，为该药材的质量标准研究提供一定的科学依据。本方法重复性较好、方法稳定、可行。     

胶带斜井在冶金矿山深井开拓中的应用探讨

针对某在建矿山深井开拓方案探索需求，通过对胶带运输系统发展应用情况介绍和胶带运输系统运输特性影响因素分析，并结合深井开拓胶带斜井方案与竖井加胶带斜井方案投资经济性比较，以及对胶带运输系统在运行过程中关键问题的分析和讨论，得出随着胶带运输技术的不断发展，在大规模深井开拓中，胶带斜井开拓将大有可为，为冶金矿山深井开拓方案选择提供决策支持。     

耦合膜分离的新型CO2低温捕集系统性能优化

CO₂捕集作为温室气体排放控制的有效手段已成为重要研究课题。作为新兴捕集技术之一，低温CO₂捕集因产品纯度高、无附加污染等优势受到关注。然而，该技术能耗和捕集率对于气体中CO₂浓度十分敏感，对于高CO₂浓度气体可获得较高的CO₂捕集率和较低能耗水平。基于此，本文提出了耦合膜分离的新型CO₂低温捕集系统，通过膜材料选择渗透性实现待捕集气体CO₂浓度主动调控，并在最优浓度下进行CO₂低温捕集。首先基于不同传统低温捕集系统特点，对比分析了不同耦合系统模式，从而确定了最优耦合系统结构。针对最优耦合系统进行了运行参数优化，并分别基于实现系统捕集能耗最低与捕集率最高的目标，获得了膜渗透侧CO₂浓度与进气CO₂浓度间的关系式，为该耦合系统中膜组件选型提供指导。研究表明，本文提出的耦合系统捕集能耗为1.92MJ/kgCO₂，相比于传统单一低温系统捕集能耗可降低16.5%。     

肠靶向海藻酸钙基微胶囊的制备及控释性能研究

利用毛细管共挤出技术结合静电吸附和仿生硅化的方法，制备了海藻酸钙-壳聚糖/精蛋白/二氧化硅(ACPSi)复合微胶囊。ACPSi复合微胶囊的平均粒径约3.18 mm，单分散性好，囊壁最外层的二氧化硅层可抑制其在肠液pH环境中的溶胀，增强囊的机械稳定性。将羟丙甲基纤维素邻苯二甲酸酯(HPMCP)肠溶微球作为释药“微阀门”，嵌入囊壁可以更好地控制微胶囊的释药行为。以吲哚美辛为模型药物，当药物浓度为22.5 mg/ml时，ACPSi载药微胶囊在pH 2.5模拟胃液中3 h时累计释药率仅为0.33%，而转移至pH 6.8模拟肠液中19 h时累计释药率为77.78%；囊壁嵌入HPMCP微球后，22 h时累计释药率可提高约4%。因此，该复合微胶囊具有良好的肠靶向作用和控释特性，作为口服肠靶向缓控释制剂具有良好的应用前景。     

干熄焦锅炉炉管失效机理分析

通过对干熄焦锅炉炉管及腐蚀产物开展系统研究，提出炉管失效原因为氧化/硫腐蚀＋高温粉尘冲刷。长寿命炉管仅耐磨层发生了较为严重的氧化及硫腐蚀，而近基体层发生了轻微氧化及硫腐蚀，基体只发生了轻微氧化；短寿命炉管耐磨层、近基体层以及基体裂纹内均发生了较为严重的氧化及硫腐蚀，且存在珠光体球化、内表面产生全脱碳层等缺陷。推测短寿命炉管存在超温现象，而超温可加剧氧化及硫腐蚀反应。此外，短寿命炉管遭受了较为严重的高温粉尘冲刷，不仅可造成炉管减薄，还会导致炉管表面温度升高。因此，减少循环气体中粉尘量尤其是大颗粒，可有效减弱冲刷以及控制炉管表面温度，是提高炉管使用寿命的关键。