摘要：Commercial aircraft family design can reduce development costs, shorten development cycles, and expand the market coverage of aircraft. Commercial aircraft family development has become one of the most important features of modern aircraft design. This paper explores the effects of commonality on different aircraft models in a commercial aircraft family. The existing product commonality indexes are summarized and their limitations in the application to aircraft design are discussed. Then a new component commonality index is proposed based on the component decomposition structure. A model for calculating the aircraft program value is established,which considers development costs, manufacturing costs, sale price, operation costs and residual costs. The effects of aircraft commonality on time and economic costs of both development and manufacturing, and on sale price, are analyzed and quantified. The commonality evaluation strategy is obtained, which features comprehensive consideration of the aircraft program value and time costs. The break-even analysis of aircraft is proceeded on the basis of costs and price data. By using a real option method, the strategy considers the uncertainty of the aircraft program and the flexibility of the manufacturer. This strategy proves to be rational and applicable to aircraft design based on the calculation of three examples and the analysis of parameter sensitivity.

摘要：高超声速飞行器要求前体与进气道一体化设计,目前已有众多前体/进气道一体化方案被提出,然而在高超声速进气道内精确有效的湍流数值计算分析方法仍有不足。本文实现了一种基于二次本构关系(Quadratic Constitutive Relation,QCR)的高精度、高效率的湍流修正模型(SA-QCR2020)。采用两种标准验证算例表明,SA-QCR2020湍流模型能够更接近真实的流动物理,对计算算例性能模拟更为准确。随后本文采用该修正湍流模型对曲面乘波进气道在侧滑角为0°,4°,8°,攻角为-8°,0°,8°工况下的性能进行了研究。结果表明,在设计工况下该曲面乘波进气道内从喉道处产生三维涡,并向后发展,随流动扩散至整个流场区域。侧滑角对进气道起动后的性能影响不大,攻角对进气道起动后的性能影响较大,且攻角越大,前缘激波越强,对来流的减速增压作用越强。研究揭示了该曲面乘波进气道在非设计工况下的性能规律,并表明该进气道能够在大攻角、大侧滑角工况下保证飞行器推进系统有效工作。

摘要：Unique MoS_(2)‐SnS_(2)heterogeneous nanoplates have successfully in‐situ grown on poly(3‐(1‐vinylimidazolium‐3‐yl)propane‐1‐sulfonate)functionalized polypyrrole/graphene oxide(PVIPS/PPy/GO).PVIPS can attract heptamolybdate ion(Mo7O246−)and Sn^(4+)as the precursors by the ion‐exchange,resulting in the simultaneous growth of 1T’‐MoS2 and the berndtite‐2T‐type hexagonal SnS_(2)by the interfacial induced effect of *** obtained MoS_(2)‐SnS_(2)/PVIPS/PPy/GO can serve as electrocatalysts,exhibiting good NRR performance by the synergistic *** semi‐conducting SnS_(2)would limit the surface electron accessibility for suppressing HER process of 1T’‐MoS_(2),while metallic 1T’‐MoS_(2)might efficiently improve the NRR electroactivity of SnS_(2)by the creation of Mo‐Sn‐Sn trimer catalytic ***,the irreversible crystal phase transition has taken place during the NRR *** 1T’‐MoS_(2)and SnS_(2)have electrochemically reacted with N_(2),and irreversibly converted into Mo^(2)N and SnxNz due to the formation of Mo−N and Sn−N bonding,meanwhile,partial SnS_(2) has been irreversibly evolved into SnS due to the reduction by the power source in the electrochemical *** would put forward a new design idea for optimizing the preparation method and electrocatalytic activity of transition metal dichalcogenides.

摘要：直流汇聚与远距离传输并网的海上风电全直流系统与交流系统相比具有诸多优点,但目前尚有系统拓扑、运维及可靠性等诸多问题未解决。直流汇聚系统现有方案故障恢复与黑启动需要的能量多依赖于独立的反向拓扑,增大了运行成本。利用提出的新型四象限隔离型DC/DC变换器拓扑的自身特性,提出和设计实现了拓扑反向重构与能量传输,为风场故障恢复与黑启动提供了低成本辅助方案。该拓扑利用反并联晶闸管构成串联谐振DC/DC变换器二次侧电路,可实现DC/DC变换器的四象限运行。首先,重点分析了拓扑反向运行模式工作原理及参数关系,并设计了反向电压闭环控制策略。其次,利用分段状态空间方程得到变换器在电感电流连续模式(continuous current mode,CCM)以及2种电感电流断续模式(discontinuous current mode,DCM)下的谐振变量时域表达式,并利用其获得反向运行时的谐振电流应力。通过时域分析法和功率守恒推导了电压增益与品质因数、开关频率之间的数学关系,划分了反向运行时的5种工况,并设计了控制策略。最后,通过MATLAB/Simulink仿真以及样机实验验证了反向运行策略的有效性。

摘要：[目的]为进一步提升水下仿生机器鱼的机动性,提高胸鳍辅助驱动效率,[方法]对胸鳍运动进行理论分析,确定影响胸鳍推力的运动参数,并提出胸鳍运动优化的3种方式,即回摇、停摇和后摇模式。通过计算流体力学(CFD)软件分析不同流速和运动频率下3种胸鳍运动模式对应的推力变化,以及胸尾鳍联合作用的推进效果。[结果]结果表明,后摇模式的阻力最小,平均推力最高,且在胸尾鳍联合驱动时较尾鳍单独驱动拥有较大的推力提升,可有效提高仿生机器鱼的机动性。[结论]研究成果可为水下仿生机器鱼的设计优化提供一定参考。

摘要：轮毂是汽车的主要组成部分之一,它的轻量化设计可以降低汽车整车重量、从而提高汽车燃油经济性。故文章基于Workbench平台,对轿车轮毂进行了拓扑优化,依据拓扑结果重构了轮毂模型,最终将轮毂重量从7.14282 kg降至5.789 kg。针对优化后的轮毂模型进行了高速旋转、径向载荷、弯曲载荷以及联合工况下的力学分析与模态分析,结果表明优化后的轮毂满足多工况的实际需求,能有效避开共振,为汽车轮毂轻量化提供了理论基础。

摘要：二维材料是指厚度仅有单层或数层原子的晶体或非晶材料,其优异的物理、力学和化学性能给纳米尺度超薄固体润滑材料的设计和发展带来了新的契机.同时,二维材料独特而简单的拓扑结构也为深入了解摩擦的微观机制提供了一个理想的对象.论文综述了以石墨烯为主的二维材料纳米尺度摩擦和磨损研究的进展.根据相对运动形式的不同,分别介绍了二维材料的层间滑动和表面摩擦行为,并详细阐述了这些独特行为背后的微观物理机制;同时还重点介绍了若干种影响和调控二维材料表面摩擦性能的典型方法和策略,以及二维材料纳米尺度的磨损行为及其失效模式.最后,还对纳米尺度二维材料摩擦研究进行了小结,并展望了该领域尚待探索的若干研究方向.

摘要：文章从北京广播电视台制作的电视公益广告《榫·卯感悟传统传承文化》入手,对公益广告在主题创意方面的推陈出新和在艺术表现形式方面的鲜明特色,以及艺术表现形式对主题的成功互动进行系统分析。通过典型案例,对新时期电视公益广告创意提出四点建议:电视公益广告必须提高政治敏锐性,紧扣时代主题;要以人为本,抓住人民群众普遍关心的问题;要不断创新艺术表现形式,让人喜闻乐见;要讲好中国故事,传播好中国声音。

摘要：Pollutant gases emitted from the civil jet are doing more and more harm to the environ- ment with the rapid development of the global commercial aviation transport. Low environmental impact has become a new requirement for aircraft design. In this paper, estimation method for emis- sion in aircraft conceptual design stage is improved based on the International Civil Aviation Orga- nization （ICAO） aircraft engine emissions databank and the polynomial curve fitting methods. The greenhouse gas emission （CO2 equivalent） per seat per kilometer is proposed to measure the emis- sions. An approximate sensitive analysis and a multi-objective optimization of aircraft design for tradeoff between greenhouse effect and direct operating cost （DOC） are performed with five geom- etry variables of wing configuration and two flight operational parameters. The results indicate that reducing the cruise altitude and Mach number may result in a decrease of the greenhouse effect but an increase of DOC. And the two flight operational parameters have more effects on the emissions than the wing configuration. The Pareto-optimal front shows that a decrease of 29.8% in DOC is attained at the expense of an increase of 10.8% in greenhouse gases.

摘要：为满足将一定规模数量的卫星快速发射至预定轨道,实现快速组网、补网的需求,对卫星在发射场的工序流程进行规划设计,以同类型、同状态的微小卫星为研究对象,深入分析卫星在发射场的任务流程,从场地、设备、工序以及人员等方面分析了其制约因素,在现有技术基础上进行了卫星并行测试和自动化对接等数字化、智能化新技术的应用探索;并在此基础上分析制定了多星交叉并行测试原则和方法,科学制定卫星规模化测试任务流程,指导任务实践;以6颗星为一组,规划设计了12颗和36颗卫星脉动式发射场任务流程,为遂行快速发射任务提供理论基础。