基于Kronecker压缩感知的宽带MIMO雷达高分辨三维成像

在宽带多输入多输出(MIMO)雷达3维成像中,MIMO雷达收发阵元数量和空间分布的限制会导致图像的2维横向分辨率难以满足实际需求。该文利用压缩感知(CS)理论来实现图像在2维横向上的超分辨。考虑到对信号的每一维分别进行超分辨会损失各维间的耦合信息,提出一种基于Kronecker CS(KCS)的2维联合超分辨方法;为解决KCS在多维高分辨应用中存储量大、计算效率低的问题,进一步提出了一种基于低分辨3维图像先验信息的降维KCS方法。仿真和实测数据实验验证了方法的有效性。     

一种不需要特征值分解的ESPRIT方法

多级维纳滤波是一种降维算法,本文提出了一种将多级维纳滤波引入到ESPRIT算法的预处理模型,提出了一种构造预处理滤波器的方法,提出了适合于ESPRIT方法的多级维纳滤波的结构。本文提出的方法避免了采样数据二阶统计的特征值分解,降低了运算量。本文方法具有一般性,适合于基于子空间方法的一大类DOA估计。仿真结果证明了方法的有效性。     

Kilogram-scale synthesis of carbon quantum dots for hydrogen evolution,sensing and bioimaging

A facile, low-cost, green, kilogram-scale synthesis of high quality CQDs were synthesized. The throughput of CQDs is 1.4975 kg in one pot and the as-prepared CQDs have a highly crystalline hexagonal structure with remarkable solubility, stability, and biocompatibility. It showed outstanding electrocatalytic activity, Fe³⁺ sensitivity and good biocompatibility.     

基于迭代二阶锥的唯相位波束形成

唯相位自适应波束形成技术对普通相控阵雷达自适应干扰抑制是非常重要的,在数字阵列雷达中,唯相位技术则可以充分利用各阵元发射模块微波功率从而提高雷达的威力。该文提出了一种新的唯相位波束形成方法,假定初始唯相位权重矢量有个较小的相位扰动,将唯相位模型的目标函数和约束函数在该相位扰动区域内分别用泰勒一阶展开式来近似,则可以将原来的非凸问题转化为凸优化问题,通过二阶锥规划方法(SOCP)求得使当前目标函数最小的扰动矢量,然后更新得到新的权重矢量并代替原来的权重矢量,重复上述迭代过程直到满足停止条件,可以得到满足要求的唯相位权重。计算机仿真结果验证了该方法的正确性和有效性。     

位敏型近贴聚焦光电倍增管的研制

报导了具有４×４矩阵阳极的位敏近贴聚焦光电倍增管的最新研究成果，以及它的基本工作原理、设计计算、性能和工艺技术难点。该管的主要技术性能指标与国外同类产品Ｒ１７１２－０１，Ｒ１７１２－０４水平相当。     

SnO_2薄膜的红外光谱和表面光电压谱的研究

本文采用PECVD方法制备了SnO_2薄膜,对薄膜进行了红外光谱和表面光电压谱测量发现,薄膜表面化学吸附O_2~(2-)和O~-离子基团,成为反应活性中心、电子转移的桥梁,推测了SnO_2表面与乙醇气体敏感反应历程.SnO_(?)薄膜淀积在n-Si上,使其表面光电压信号增强二个数量级以上,我们认为是SnO_2/n-Si异质结作用和消反射作用的结果.     

A new algorithm for 2-D DOA estimation

In this paper we present a new algorithm to estimate the 2-D direction of arrival (DOA) of narrowband sources lying in the far field of the array. The array consists of matched co-directional triplets, and can be considered as an extension of the 1-D ESPRIT scenario to 2-D. The proposed approach is simple and direct and does not require a search procedure or initialization. Existing algorithms require a search to match the correct elevation and azimuth angles and are computationally more expensive. This technique automatically pairs the azimuth and elevation angles by marking them. The computational complexity is twice that of 1-D ESPRIT. Simulation results and comparisons with other existing algorithms are presented to demonstrate the performance of the proposed technique.     

基于Mn掺杂ZnS量子点的室温磷光传感应用的研究进展

与一般有机染料分子相比,半导体材料量子点具有优异的光学性能,在多个领域得到了广泛的应用.量子点具有窄而对称且可调的发射波长、宽激发强吸收、抗光漂白能力强以及水溶性好等诸多优势,引起了研究者广泛关注.为了增加量子点的斯托克斯位移从而很好地避免量子点的自猝灭现象,引入掺杂物是一种很有效的方式.掺杂量子点不仅保留了量子点原有的优点,而且还赋予量子点额外的优异性能.如Mn掺杂ZnS量子点生物相容性好,不含Cd和Hg等有害元素,而且Mn2+的加入使其具有优异的室温磷光特性.磷光检测能很好地避开生物背景荧光的干扰,使得Mn掺杂ZnS量子点能够广泛应用于磷光生物分析.本文综述了Mn掺杂ZnS量子点在室温磷光分析中的研究进展,着重介绍了几种具有启发意义的设计策略,包括其发光机理以及应用于离子、分子以及生物大分子等的检测.     

Two-step synthesis of Bi2Te3-Te nanoarrays with sheet-rod multiple heterostructure

Bi₂Te₃-Te arrays with sheet-rod multiple heterostructure were obtained in large scale, using Te nanorod arrays as the in-situ templates under solvothermal process. The array is formed by the ordered Bi₂Te₃-Te rods where Bi₂Te₃ sheets distribute from the top face to the bottom face along the Te rod vertically. The microstructure of the heterostructure was studied through X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The electrical conductivity and Seebeck coefficient of the arrays were also studied. The course of reaction was monitored so as to propose a possible growth mechanism of such novel heterostructure. The key for the preparation of such heterostructure is to balance the velocity between the dissolution of Te rods and the formation of Bi₂Te₃ sheets. This synthetic approach could be promising to prepare self-assembled low-dimensional nanoarrays of metals and semiconductors with high yield.     

基于FPGA的AD7862接口电路设计

针对在自动控制系统设计领域和通信领域中有着广泛运用的AD7862芯片,介绍了一种基于FPGA的驱动接口电路的设计。阐述了AD7862的特点及基本功能,以及基于这些功能特点的驱动时序,并以此时序为基础在FPGA芯片中实现了AD7862的驱动电路。给出了主要的VHDL代码以及最终的仿真测试结果,实现了对AD7862芯片的稳定可靠驱动,同时也验证了所设计驱动电路的正确性。