宽频段太赫兹辐射计高吸收率涂层的特性

为了对宽频段高吸收率太赫兹辐射计的特性进行表征,研究了吸收涂层材料的特性;对常见的吸波材料在太赫兹波段的吸收率进行仿真,探寻在太赫兹波段具有高吸收率的材料;将碳化硅与3M黑漆进行混合,以进一步提高涂层的吸收率,并通过仿真调整涂层内碳化硅颗粒的尺寸;根据仿真结果制备混合涂层,利用太赫兹时域光谱仪对混合涂层样品进行测量。结果表明:该混合涂层样品的光谱吸收率大于0.99,与仿真结果基本吻合。     

“双驱动足”回转式压电马达初步研究

提出一种“双驱动足”回转式压电马达，分析了其工作原理，并根据工作原理，设计，研制了样机，进行了初步的试验研究，证明工作原理基本正确，为今后进一步研究提供了参考依据。     

Low Complexity Time Domain Interleaved Partitioning Partial Transmit Sequence Scheme for Peak-to-Average Power Ratio Reduction of Orthogonal Frequency Division Multiplexing Systems

As an attractive technique for peak-to-average power ratio (PAPR) reduction in orthogonal frequency division multiplexing (OFDM) systems, time domain interleaved partitioning partial transmit sequence (TD-IP-PTS) scheme uses circular convolution property of discrete Fourier transforms (DFT) so as to need only one inverse fast Fourier transform (IFFT) operation. However, the search and combination of phase factors still need higher computational complexity. In order to improve the problem, this paper detailedly analyzes the independence of phase factor vectors and optimizes the phase factor vectors in TD-IP-PTS. Furthermore, we find the characteristic of combination of phase factors and propose three methods respectively based on storage-unit, pipeline and select-path to implement the combination of phase factors in TD-IP-PTS. The simulation results show that TD-IP-PTS using independent and effective phase factor vectors has better PAPR performance and lower complexity than traditional IP-PTS. Moreover, among three proposed methods for combination of phase factors, the method based on select-path requires the least registers and delay time. This method is the most promising in practical applications.     

无线物联网中的频谱感知模型研究

In the last few years, the number of devices operating in wireless Internet of Things (IoT) has experienced tremendous growth. On the other hand, the growth results in spectrum scarcity. Cognitive Radio (CR) systems have been proposed to efficiently exploit the spectra that have been assigned but are underutilized. In this paper, a spectrum sensing model based on Markov chain is proposed to predict the spectrum hole for CR in wireless IoT. Theoretical analysis and simulation results have been evaluated that a Markov model with two-state or four-state works well enough in wireless IoT whereas a model with more states is not necessary for it is complex.     

串联聚能射流的数值模拟与实验研究

为了有效对付各种现代装甲目标,提出一种新型聚能装药结构并探讨了其成型机理.应用有限元软件分别对其前级装药、后级装药以及双级串联聚能装药的射流侵彻过程进行了数值模拟.结果表明:该串联装药可生成两个稳定且具有高同轴度的金属射流,其穿深比单锥角药型罩至少高30%.并在此基础上进行了系列的静破甲实验,实验与数值模拟结果吻合较好, 进一步深化了聚能效应的内涵和丰富了打击目标的手段.     

车载火箭炮行军动力学研究

车载火箭炮在行驶中,路面激励产生的动载荷会对火箭炮的零部件产生破坏作用,从而影响火箭炮的使用寿命。通过分析全炮的拓扑结构,用RECURDYN、ANSYS软件,建立了车炮在行驶状态下的刚柔耦合模型。在实际建模中,取大梁为柔体。根据相关军用标准,编制六种路面谱。对六种路况进行行军分析,获得了相关零部件的动态参数。为某新型火箭炮的总体设计及零部件设计提供依据。     

Carrier Transport Enhancement Mechanism in Highly Efficient Antimony Selenide Thin-Film Solar Cell

Exhibiting outstanding optoelectronic properties, antimony selenide (Sb₂Se₃) has attracted considerable interest and has been developed as a light absorber layer for thin-film solar cells over the decade. However, current state-of-the-art Sb₂Se₃ devices suffer from unsatisfactory “cliff-like” band alignment and severe interface recombination loss, which deteriorates device performance. In this study, the heterojunction interface of an Sb₂Se₃ solar cell is improved by introducing effective aluminum (Al³⁺) cation into the CdS buffer layer. Then, the energy band alignment of Sb₂Se₃/CdS:Al heterojunction is modified from a “cliff-like” structure to a “spike-like” structure. Finally, heterojunction interface engineering suppresses recombination losses and strengthens carrier transport, resulting in a high efficiency of 8.41% for the substrate-structured Sb₂Se₃ solar cell. This study proposes a facile strategy for interfacial treatment and elucidates the related carrier transport enhancement mechanism, paving a bright avenue to overcome the efficiency bottleneck of Sb₂Se₃ thin-film solar cells.     

高超声速航天器最优再入大回转轨迹与控制

研究了飞回型可重复使用航天器以高超声速再入返回的最优大回转轨迹设计和轻制方法,分析了飞回型航天器再入中靠气动力实现轨迹大回转的关键技术,建立了最优再入的数学模型.采用极大值原理和共轭梯度法求解最优再入大回转问题.通过仿真,得到了考虑大回转的最优再入轨迹特性及其控制规律,分析了转弯开始时刻和滚转角对再入中倾斜转弯控制特性的影响规律.探讨了高超声速大回转再入的控制方法.     

金属靶板扩孔冲塞穿孔弹头临界锥角分析

研究了刚性锥头弹垂直贯穿金属靶板扩孔冲塞型穿孔模式,在理想弹塑性材料两阶段工程模型的基础上,考虑靶板为硬化材料,得到扩孔冲塞型穿孔弹头临界半锥角及相应的弹道极限.分析了弹头长度、弹丸质量和靶板材料参数对临界半锥角的影响.计算结果与已有试验结果吻合较好.     

基于能带调制模型的高压增强型AlGaN/GaN HFET器件

提出了一种能带调制模型,通过在异质结界面处引入负离子电荷(如氟离子)调制异质结处的局部能带分布,实现了对异质结界面处的高密度2DEG的改变。基于能带调制模型,提出了一种复合调制沟道AlGaN/GaNHFET器件。通过在增强型沟道调制区和RESURF调制区分别引入不同剂量的负离子,不仅实现了增强型器件,而且可以降低尖峰电场,优化异质结电场分布,提高器件击穿电压。通过器件仿真软件对其器件工作原理进行了模拟分析,并通过实验结果表明,其器件品质因子FOM由传统器件的4.8MW.cm-2提高到26.7MW.cm-2。