摘要：An aperture design technique using multi-step amplitude quantization for two-dimensional solid-state active phased arrays to achieve low sidelobe is described. It can be applied to antennas with arbitrary complex aperture. Also, the gain drop and sidelobe degradation due to random amplitude and phase errors and element (or T/R module) failures are investigated.

摘要：Opportunistic array radar （OAR） is a new generation radar system based on the stealth of the platform, which can improve the modern radar performance effectively. Designing the orthogonal code sets with low autocorrelation and cross-correlation is a key issue for OAR. This paper proposes a novel hybrid genetic algorithm （HGA） and designs the polyphase orthogonal code sets with low autocorrelation and cross-correlation properties, which can be used in the OAR system. The novel algorithm combines with simulated annealing （SA） and genetic algorithm （GA）, adds in keeping best individuals and competition in small scope, and introduces grey correlation evaluation to evaluate fitness function. These avoid the premature convergence problem existed in GA and enhance the global searching capability. At last, the genetic results are optimized to obtain the best solution by using greedy algorithm. The simulation results show that the proposed algorithm is effective for the design of orthogonal phase signals used in OAR systems.

摘要：An experimental double-layer active frequency-selective surface（AFSS） for stealth radome is proposed. The AFSS is a planar structure which is composed of a fixed frequency-selective surface（FSS）, a PIN diodes array, and a DC bias network. The AFSS elements incorporating switchable PIN diodes are discussed. By means of controlling the DC bias network, it is possible to switch the frequency response for reflecting and transmitting. Measured and simulated data validate that when the incidence angle varies from 0°to 30° the AFSS produces more than-11.5 dB isolation across6–18 GHz when forward biased. The insertion loss（IL） is less than 0.5 dB across 10–11 GHz when reverse biased.

摘要：For the gray attributes of the equipment program and its difficulty to carry out the quantitative assessment of the equipment program information, the gray relation projection method is simply reviewed. Combining the super-data envelopment analysis（DEA） model and the gray system theory, a new super-DEA for measuring the weight is proposed, and a gray relation projection model is established to rank the equipment programs. Finally, this approach is used to evaluate the equipment program. The results are verified valid and can provide a new way for evaluating the equipment program.

摘要：A gallium nitride(GaN)power amplifier monolithic microwave integrated circuit(MMIC)with a wide band and high efficiency in the microwave frequency band is proposed in this *** power amplifier MMIC uses a 0.15^im GaN high electron mo-bility transistor(HEMT)*** operating frequency band of the amplifier can cover the whole K-band,i.e.,17-26.5 GHz.

摘要：Contact engineering is of critical importance for two-dimensional(2D)transition metal dichalcogenide(TMD)-based ***,there are only a few solutions to overcome this obstacle because of the complexity of the TMD-contact *** this work,we propose a novel method using a soft plasma treatment followed by the seamless deposition of a metal electrode to reduce the contact resistance of MoS_(2)field effect transistors(FETs).The treated FETs exhibit three times higher mobility than the control FETs without plasma *** soft plasma treatment can remove the facial sulfur atoms and expose the middle Mo atoms so that they come into direct contact with the metal electrode,thus greatly improving the contact ***-principles calculation is also performed to support the experimental *** potentially scalable strategy can be extended to the whole family of TMD based FETs to provide a possible route of device processsing technology for 2D device application.

摘要：径流预报对防洪具有重要意义。然而,由于径流过程的复杂性和随机性,对日径流量进行准确预测是困难的,尤其是对峰值径流量的预测。为了解决这一问题,本研究提出了一种用于径流预测的增强型长短期记忆(LSTM)模型,其中引入了新的损失函数并集成了特征提取器。设计了峰值误差tanh(peak error tanh,PET)和峰值误差swish(peak error swish,PES)两个损失函数,增强了峰值径流预测的重要性,弱化了正常径流预测的权重。为每个气象站建立由3个LSTM网络组成的特征提取器,目的是提取每个气象站输入数据的时间特征。以中国淮河上游为例,利用增强型LSTM模型对1960—2016年的日径流量进行了预测。结果表明,改进后的LSTM模型表现良好,在验证期内(2005年11月至2016年12月),Nash-Sutcliffe效率(NSE)系数在0.917-0.924之间,优于广泛使用的集总水文模型(Australian Water Balance model(AWBM)、Sacramento、Sim Hyd和Tank模型)和数据驱动模型(人工神经网络(ANN)、支持向量回归(SVR)和门控循环单元(GRU))。以PES为损失函数的增强型LSTM对洪水极端径流的预测效果最好,平均NSE为0.873。此外,海拔较高的气象站降水对径流预测的贡献比最近的气象站更大。该研究为流域日径流预测提供了有效工具,有利于流域防洪和水安全管理。

摘要：Combining the mutual information theory and the sequential hypothesis testing(SHT)method,a selfadapting radio frequency(RF)stealth signal design method is proposed. The channel information is gained through the radar echo and feeds back to the radar system,and then the radar system adaptively designs the transmission waveform. So the close-loop system is formed. The correlations between these transmission waveforms are decreased because of the adaptive change of these transmission waveforms,and the number of illuminations is reduced for adopting the SHT,which lowers the transmission power of the radar system. The radar system using the new method possesses the RF stealth performance. Aiming at the application of radar automatic target recognition(RATR),experimental simulations show the effectiveness and feasibility of the proposed method.

摘要：Quantum secure direct communication(QSDC)attracts much attention for it can transmit secret messages directly without sharing a *** this article,we propose a one-step QSDC protocol,which only requires to distribute polarization-spatial-mode hyperentanglement for one *** this QSDC protocol,the eavesdropper cannot obtain any message,so that this protocol is unconditionally secure in *** protocol is a two-way quantum communication and has high capacity for it can transmit two bits of secret messages with one pair of *** entanglement fidelities of both polarization and spatial-mode degrees of freedom being 0.98,the maximal communication distance of this onestep QSDC can reach about 216 *** can also be used to generate the *** this regard,the key generation rate is estimated about 2.5 times of that in the entanglement-based QKD with the communication distance of 150 *** the help of future quantum repeaters,this QSDC protocol can provide unconditionally secure communication over arbitrarily long distance.

摘要：MXene具有丰富的高电负性末端原子、较大的比表面积和较小的原子厚度等优点,已被用作前驱体制备多种纳米材料.然而,目前已报道的用于衍生金属有机框架(MOF)的MXene仅限于V_(2)CT_(x).因此,通过增加MXene和有机配体的种类,合理设计和合成新型MOF,并进一步深入探索其合成机理仍是目前面临的重要挑战.本文采用金属离子辅助转化策略,以二维Ti_(3)C_(2)T_(x)为前驱体,合成了具有非互穿SrSi2(srs)框架的基于儿茶酚的三维(3D)TiCu-HHTP(HHTP=2,3,6,7,10,11-六羟基三苯)MOF.该策略表现出了良好的普适性,Ti3C2和辅助Cu^(2+)离子可以扩展到V2C MXene和其他辅助金属离子Mn^(+)(M=Ni^(2+)、Co^(2+),Mn^(2+)和Zn^(2+)).转化机制包括从Ti3C2纳米片到辅助金属离子的电荷转移、Ti-C键断裂促进释放Ti^(4+)离子以及Ti^(4+)/Mn^(+)与HHTP之间的强螯合配位协同促进TiCu-HHTP的形成.独特的3D导电网络和丰富的氧化还原位点赋予了TiCu-HHTP-7/PPy复合柔性透明电极快速的离子/电子传输和可逆的法拉第反应.在0.02 mA cm^(-2)电流密度下,TiCu-HHTP/PPy透明电极的面积比电容值达到3.63 mF cm^(-2),明显高于纯PPy电极的面积电容值(1.79 mF cm^(-2)).TiCu-HHTP/PPy透明电容器在0.75μW cm^(-2)的功率密度下,能量密度为0.042μWh cm^(-2).