摘要：In order to search for high energy density materials,various 4,8-dihydrodifurazano[3,4-b,e]pyrazine based energetic materials were *** functional theory was employed to investigate the relationships between the structures and *** calculated results indicated that the properties of these designed compounds were influenced by the energetic groups and heterocyclic ***-N3 energetic group was found to be the most effective substituent to improve the heats of formation of the designed compounds while the tetrazole ring/-C(NO_(2))_(3) group contributed much to the values of detonation *** analysis of bond orders and bond dissociation energies showed that the addition of-NHNH2,-NHNO_(2),-CH(NO_(2))_(3) and-C(NO_(2))_(3) groups would decrease the bond dissociation energies *** A8,B8,C8,D8,E8,and F8 were finally screened as the potential candidates for high energy density materials since these compounds possess excellent detonation properties and acceptable thermal ***,the electronic structures of the screened compounds were calculated.

摘要：膝骨关节炎(knee osteoarthritis,KOA)是一种常见的膝关节退行性疾病,病理特征为滑膜炎症、软骨丢失等,常表现为关节疼痛和活动功能受限,严重影响患者的生活质量。传统治疗手段,如药物注射和手术干预,主要致力于缓解症状,对于软骨的修复效果有限。人脐带间充质干细胞(human umbilical cord mesenchymal stem cells,hUC-MSCs)因具有抗炎和软骨再生能力,成为治疗KOA的新希望。本文结合国内外最新研究成果,对临床中应用hUC-MSCs治疗KOA的理论依据、研究设计及疗效评价进行论述,同时围绕hUC-MSCs临床应用中面临的问题,以及未来需攻克的方向展开探讨,以期为临床应用hUC-MSCs治疗KOA提供理论支持。

摘要：Combination antiretroviral therapy(ART)reduced AIDS-related mortality and increased survival among patients living with HIV by interrupting HIV replication,enhancing immune recovery,and preventing the onset of opportunistic infections[1].In China,ART has rapidly been scaled up since the beginning of the National Free Antiretroviral Treatment Program(NFATP)in 2003[2].By the end of 2016,489,411 individuals diagnosed with HIV were receiving free antiretroviral treatment in *** is firmly committed to reducing overall AIDS-related mortality and HIV incidence within the ***,similar to other low-and middle-income countries,the NFATP is challenged by high mortality and attrition shortly after patients initiate ART[3].

摘要：This paper describes a novel model known as the shadow obstacle model to generate a realistic comer-tuming behavior in crowd simulation. The motivation for this model comes from the observation that people tend to choose a safer route rather than a shorter one when turning a comer. To calculate a safer route, an optimization method is proposed to generate the corner-turning rule that maximizes the viewing range for the agents. By combining psychological and physical forces together, a full crowd simulation framework is established to provide a more realistic crowd simulation. We demonstrate that our model produces a more realistic comer-turning behavior by comparison with real data obtained from the experiments. Finally, we per- form parameter analysis to show the believability of our model through a series of experiments.

摘要：设计变电站远程智能巡检图像目标快速识别算法,通过高效的目标识别性能,提升变电站巡检水平。利用无人机搭载相机,采集变电站远程智能巡检图像,通过小波变换方法滤波处理所采集的智能巡检图像。利用自适应阈值分割方法,分割已滤波处理的变电站远程智能巡检图像,将智能巡检图像划分为前景图像与背景图像。以智能巡检图像的前景图像为基础,构建高斯差分金字塔,提取图像的SIFT特征。依据所提取智能巡检图像的SIFT特征构建样本集,作为特征加权支持向量机的输入,利用特征加权支持向量机输出目标快速识别结果。实验结果表明,该算法可以快速识别变电站远程智能巡检图像中的目标,目标识别时间低于500 ms。

摘要：钙钛矿型铁电氧化物由于具有本征的、非易失的、可翻转的自发极化以及带有高电荷密度的极性表面等特性,被认为是最有前途的功能材料之一.研究钙钛矿型铁电氧化物的表面结构对理解其表面/界面能量转化、调控表面物质吸附和脱附、控制界面化学反应、以及设计稳定的低功耗电子器件具有重要意义.本文首先概述了铁电相与其表面结构的关系,并介绍了钙钛矿型铁电氧化物复杂表面结构的形成;之后阐述了铁电表面/界面结构的调控机制,为后续的钙钛矿型铁电氧化物的表面结构设计、表面性能与功能的控制提供了研究基础;最后介绍了铁电氧化物表面/界面的功能调控和潜在器件的设计,并结合目前铁电材料领域表面科学研究的局限性,对今后基于钙钛矿型铁电氧化物表面结构的研究发展以及应用前景提出了展望.

摘要：流体在临界点附近参数区域,其黏性系数、比热容、导热系数、密度等热物理性质都会发生剧烈变化,因此超临界流体在多孔介质中的渗流特性较为复杂,常规流体多孔渗流压降特性规律能否适用有待于验证。以超临界水煤气化技术为代表的一系列高新技术的发展对多孔介质中超临流体的渗流特性的认识提出了更高的要求。本文考察了典型操作参数(温度300~450℃,压力22.7~25 MPa,流量0.8~3 kg.h^(-1))对多孔介质中超临界水渗流压降特性的影响。研究结果表明:Ergun公式在估算多孔介质中超临界水渗流压降的过程,黏性项被高估,惯性项被低估。本工作有望为超临界水煤气化技术中超临界水流化床的设计提供依据。

摘要：针对低轨存储转发星座的特点以及传统星座设计方法无法同时优化覆盖性能和网络性能的不足,该文提出一种新型的兼顾覆盖性能以及网络性能的低轨存储转发星座设计方法,并采用非劣分层多目标进化算法(NSGA-II)优化该多目标多约束星座设计问题。通过基于STK和OPNET的协同优化仿真平台验证了该星座设计方法的有效性。

摘要：针对ZDPS-2卫星的高实时性要求,设计多路并行独占式DMA,实现CPU与包括载荷在内的所有部件的高效交互:54路外设串行接口通信占用CPU时间由565ms降低到50ms,姿控系统传感器数据采集时间一致性由33ms降低到6ms.设计数据混编传输机制及链式DMA结构,实现84路载荷数据100 Hz高频采集与实时下传,满足40ms下传延时要求.通过关键器件抗辐射加固及系统容错机制,提高系统的可靠性.地面测试与在轨运行结果表明:综合电子系统功能正确,稳定可靠,已在轨连续运行5个多月,完成了载荷及各项试验,实时性满足任务需求.

摘要：针对低轨同构星座覆盖资源在纬度上分布不均匀的不足,提出采用低轨混合星座提升覆盖均匀性的设计方案,并推导了满足全球任意点平均每天覆盖一定次数的最小卫星规模估算公式。针对非支配近邻免疫算法(NNIA)约束处理方面的不足,提出基于约束支配的改进非支配近邻免疫算法(Modified NNIA),并以此设计了一种低轨混合星座优化平台来优化带约束的星座设计问题。仿真结果表明,改进的NNIA算法在收敛速度和多样性上均优于非支配分层遗传算法(NSGA-II)和多目标粒子群算法(MOPSO),可大大提高星座设计的效率。同时优化结果也表明低轨混合星座可提高覆盖的均匀性和大部分区域的覆盖次数,进而减少特定覆盖要求所需的卫星数目。