摘要：Magnesium alloys have shown prospective applications as a new biodegradable metal within bone. To garantee the longterm biocompatibility, a Mg-Zn-Ca alloy,composing of essential elements for human, was prepared and its feasibility for orthopedic applications was investigated. The in vitro and in vivo corrosion of Mg-Zn-Ca alloy as well as the biocompatibility were studied. The in vitro corrosion tests in five kinds of physiological solutions showed that the corrosion rates and corrosion morphologies of the alloy were strongly influenced by the solution used. The addition of serum in Hank’s and MEM significantly slowed down the corrosion rate and improved the corrosion uniformity of the alloy. The corrosion rate decreased with increasing serum *** alloy showed the slowest corrosion rate as well as homogeneous corrosion morphology in MEM＋10%FBS. Both the indirect and direct cell experiments indicated good cytocompatibility of the extruded Mg-Zn-Ca alloy. In vivo, we observed a gradual degradation process from the surface of extruded Mg-Zn-Ca alloy and only 40% in volume of implant was left after 4 weeks implantation in medullary cavities of mice. The micro-CT and histological analyses revealed its good biocompatibility with peri-implant new bone formation and increasing cortical bone thickness with increasing implantation period. This study showed that the extruded MgZn-Ca alloy provided sufficient biocompatibility for orthopedic application, though the in vivo corrosion rate should be further reduced for clinical use.

摘要：背景:植入体内后,血管支架处于复杂的应力及腐蚀环境,可引发支架应力腐蚀开裂及腐蚀疲劳断裂,导致支架早期失效。目的:综述不同生理应力环境下可降解金属支架的降解情况及其降解机制。方法:检索PubMed数据库、中国知网数据库2000至2018年发表的文献,英文检索词为"biodegradable,degradation,stress",中文检索词为"镁合金,应力腐蚀"。结果与结论:镁、铁和锌是目前最具代表性的3种可降解金属材料,在血管支架领域具有良好的应用前景。可降解支架植入体内后,支撑血管直至其完成血管重建,在此过程中支架受到复杂的应力作用,包括拉应力、压应力、剪切应力及循环荷载等。应力对支架降解的影响不可忽视,其可加快支架力学性能的衰减,甚至导致支架断裂。探明应力对可降解金属降解行为的影响及其降解机制,对血管支架材料的改性、支架构型设计与优化至关重要。

摘要：面向源网互动的日前调度问题需要考虑多项目标,同时针对多个时段进行优化。在分析互动资源特性基础上,将可控型DG的出力及端电压、微电网与配电网的交换功率、开关状态作为控制量,提出考虑电压偏移、网损、负荷波动、开关动作次数几项指标,基于矩阵编码的智能配电网日前调度方法。以86节点配电网为基础设计仿真算例,仿真结果证明了模型和算法的有效性。

摘要：阐述光谱椭偏测量技术基本原理和椭偏测量数据分析方法,发展宽光谱穆勒矩阵椭偏仪等先进光谱椭偏测量技术和仪器。利用光谱椭偏测量技术精确标定典型OLED(organic light-emitting diode)材料基础光学数据,分析揭示有机材料分子取向及其导致的光学各向异性。构建复杂叠层有机发光器件光学计算模型,模拟分析其关键性能参数,提出光学协同优化设计方法,指导高性能OLED器件设计。结果和讨论展示了光谱椭偏技术在OLED材料与器件表征以及高性能OLED器件设计中的应用。

摘要：依据DL/T 5044-2014规定的短路电流计算方法,结合直流断路器的动作特性,对常规发电厂直流电源系统存在的选择性问题进行了分析,提出了采用具有熔断器特性的直流断路器、具有短路短延时特性的三段式直流断路器和具有限流特性的二段式相结合的过电流选择性保护解决方案。该方案满足发电厂直流系统保护电器要求,是发电厂直流电源过电流保护系统的最佳选择。