Quantum plasmons in the hybrid nanostructures of double vacancy defected graphene and metallic nanoarrays

We study the plasmonic properties of hybrid nanostructures consisting of double vacancy defected graphene(DVDGr)and metallic nanoarrays using the time-dependent density functional theory. It is found that DVDGr with pure and mixed noble/transition-metal nanoarrays can produce a stronger light absorption due to the coherent resonance of plasmons than graphene nanostructures. Comparing with the mixed Au/Pd nanoarrays, pure Au nanoarrays have stronger plasmonic enhancement. Furthermore, harmonics from the hybrid nanostructures exposed to the combination of lasers ranged from ultraviolet to infrared and a controlling pulse are investigated theoretically. The harmonic plateau can be broadened significantly and the energy of harmonic spectra is dramatically extended by the controlling pulse. Thus, it is possible to tune the width and intensity of harmonic spectrum to achieve broadband absorption of radiation. The methodology described here not only improves the understanding of the surface plasmon effect used in a DVDGr-metal optoelectronic device but also may be applicable to different optical technologies.     

高温环境下结构模态试验技术

由于高超声速飞行器长时间在大气层内工作会面临恶劣的气动热环境,飞行器结构地面模态试验必须考虑高温影响,但高温环境下结构模态试验远比常规试验复杂,目前仍存在很多技术难点亟待解决.本文首先对高温环境下的结构模态试验技术国内外发展现状进行了综述,详细分析了现有的高温环境下结构模态试验中的激励力与振动响应测量技术的特点及适用性,最后展望了高温环境下结构热模态试验技术的发展方向和研究重点.     

循环冲击载荷作用下页岩动力学响应及能量耗散特征

采用$\varnothing $50 mm分离式霍普金森杆(split Hopkinson pressure bar,SHPB)实验系统开展页岩循环冲击实验,研究不同循环冲击载荷作用下页岩动力学响应及损伤演化特征,同时揭示了控制入射总能量不变条件下,不同气压梯度循环冲击页岩能量演化规律。随着冲击气压升高,试样破裂所需的冲击次数呈线性减少,峰值应力随循环冲击次数的增加先升高后降低,极限应变先减小后增大,试样在循环冲击下表现出先压密后损伤的力学机制。基于Weibull分布的统计损伤模型表明,升高循环冲击气压,试样损伤破坏形式由缓慢劣化逐渐转变为骤然破坏。入射总能量恒定的情况下,通过控制循环入射能量梯度能够产生不同的损伤效果,降压冲击和升压冲击下的能量吸收比均大于恒压冲击下的,且气压梯度的绝对值与能量吸收比呈现正相关性。

     

一种加权均方误差最小化的鲁棒性干扰对齐算法

线性干扰对齐的一个常见优化目标是总传输速率最大化,但因为和速率函数的非凸特性而难以直接求解。加权均方误差最小化算法借助均方误差与和速率之间的等价关系解决了这一问题。这一方法需要获得准确的信道状态信息,在实际应用中,通道估计误差的存在会导致算法性能的下降。该文提出一种改进算法,在干扰对齐预编码矩阵与接收矩阵的优化求解过程中将通道估计误差的统计特性考虑在内。仿真结果表明,相比以往的加权均方误差最小化算法,该文算法对信道估计误差具有较高的鲁棒性,可以有效提高总的传输速率。     

基于容量相关字典的5G毫米波大规模天线单元选择算法

针对传统天线选择算法在大规模天线阵列应用中的局限性,该文在多用户场景下提出一种基于容量相关字典的5G毫米波大规模天线随机选择算法。该算法通过特定环境中不同位置处的多用户与基站的交互,快速提取大规模天线单元间容量的强弱相关特性,并建立相关字典;在天线选择时,先搜索最优信道容量单元连接射频链路,再随机选择相关字典中与最优单元容量相关大的天线单元接入其余射频链路。该方法大大降低了传统天线选择算法应用的复杂度,只与环境有关且较为稳定,当新用户加入时也无需重新建立相关字典。该方法通过损失一部分性能来换取较低的复杂度,适用于天线单元多的大规模天线阵列。此外,该文在室内开放式办公室开展了26 GHz视距和非视距下的大规模天线信道测试,分析了不同场景下的天线阵列行间单元间的容量相关性,并对该算法的系统信道容量性能进行了实验验证。     

Investigating the Mechanisms of Bisdemethoxycurcumin in Ulcerative Colitis: Network Pharmacology and Experimental Verification

Ulcerative colitis is a chronic inflammatory bowel disorder that is hard to cure once diagnosed. Bisdemethoxycurcumin has shown positive effects on inflammatory diseases. However, the underlying bioactive interaction between bisdemethoxycurcumin and ulcerative colitis is unclear. The objective of this study was to determine the core target and potential mechanism of action of bisdemethoxycurcumin as a therapy for ulcerative colitis. The public databases were used to identify potential targets for bisdemethoxycurcumin and ulcerative colitis. To investigate the potential mechanisms, the protein-protein interaction network, gene ontology analysis, and Kyoto encyclopedia of genes and genomes analysis have been carried out. Subsequently, experimental verification was conducted to confirm the findings. A total of 132 intersecting genes of bisdemethoxycurcumin, as well as ulcerative coli-tis-related targets, were obtained. SRC, EGFR, AKT1, and PIK3R1 were the targets of highest potential, and the PI3K/Akt and MAPK pathways may be essential for the treatment of ulcerative colitis by bisdemethoxycurcumin. Molecular docking demonstrated that bisdemethoxycurcumin combined well with SRC, EGFR, PIK3R1, and AKT1. Moreover, the in vitro experiments suggested that bisdemethoxycurcumin might reduce LPS-induced pro-inflammatory cytokines levels in RAW264.7 cells by suppressing PI3K/Akt and MAPK pathways. Our study provided a comprehensive overview of the potential targets and molecular mechanism of bisdemethoxycurcumin against ulcerative colitis. Furthermore, it also provided a theoretical basis for the clinical treatment of ulcerative colitis, as well as compelling evidence for further study on the mechanism of bisdemethoxycurcumin in the treatment of ulcerative colitis.     

nBn型InAs/GaSbⅡ类超晶格红外探测器光电特性研究

设计了nBn结构的InAs/GaSb II类超晶格红外探测器,从理论和实验两方面对nBn器件的暗电流特性进行了研究,研究结果表明：理论计算的暗电流和实际测试结果趋势一致。另外,研制了p-i-n结构器件并与nBn器件进行了比较,测试结果显示：在77 K温度下,nBn器件的暗电流要比p-i-n器件暗电流小2个量级。温度升高到150 K时,nBn器件暗电流变大2个量级,而p-i-n器件暗电流变大4个量级;nBn器件峰值探测率下降到1/5,p-i-n器件峰值探测率下降2个量级。可见nBn器件适合高温工作,适合高性能红外焦平面探测器的研制。     

InGaAs固体微光器件研究进展

InGaAs器件具有光谱响应宽、量子效率高、响应速度快、数字化读出、高温工作、可靠性好以及寿命长等优点,符合新一代微光器件的发展需求,在国际上成为固体微光器件的一种新选择,获得了重要的发展和应用。文章就 InGaAs 固体微光器件材料属性、器件性能以及成像特点等几方面进行了详细分析,介绍了当前InGaAs器件的发展趋势,以及研制320×256 InGaAs阵列的最新进展。研究结果表明 InGaAs 材料生长及器件工艺具有较好的可控性和稳定性,为实现高性能、实用化的InGaAs固体微光器件提供了技术支撑。     

线性调频信号主瓣不展宽旁瓣抑制方法

以汉明窗为代表的加权方法在抑制线性调频信号的匹配滤波输出峰值旁瓣的同时展宽主瓣,致使距离分辨力下降。为兼顾旁瓣抑制和高距离分辨力的需求,该文提出一种新的主瓣不展宽旁瓣抑制方法。该方法首先将匹配滤波和加权处理的输出幅度进行归一化处理,然后逐点进行比较,再取各点对应的最小值作为最终的输出数据。该方法兼取了匹配滤波和加权处理的优点,其-3 dB主瓣展宽系数与匹配滤波相比仅为1,而旁瓣抑制性能和对应的加权处理相当。仿真结果和湖上试验验证了该方法的有效性。     

外辐射源天地波雷达定位方法及精度分析

天地波组合传播模式高频外辐射源雷达受电离层和海洋表面环境、短波段电磁环境及收发配置等诸多因素的影响. 针对该新体制外辐射源雷达的定位问题,研究了天地波组合传播模式下的目标定位模型,提出了一种基于直达波到达仰角的定位新方法,并分别从测量误差理论和几何精度因子(Geometric Dilution Of Precision,GDOP)两方面分析了定位精度与目标方位的关系. 仿真结果表明,在简化定位模型的情况下,利用该方法的定位结果在一定区域内仍然具有较高的定位精度,根据研究结果有针对性地提供了改善定位精度的工程方案.