Highly efficient magnetically tunable high frequency spur-line notch filter

We report a cobalt ferrite nanorods (CFO NRs) based magnetically tunable spur-line notch filter where vertically aligned CFO NRs has been grown on silver nanoparticles coated silicon substrate. The CFO NRs are coupled with high frequency spur-line bandstop filter in flip-chip configuration and the device showed excellent tunable microwave properties in the presence of a low bias magnetic field. The center frequency of the tunable filter is ~16.4 GHz which is shifted to ~14.9 GHz with ~8.7% tunability by applying bias magnetic field ~320 Oe. The magnetic field tuning of the center frequency is explained on the basis of the change in permeability value of the CFO NRs with bias magnetic field as the NRs are used in the partially magnetized state. For validation, permeability value is also calculated by using numerical equations. The experimental reflection of the device has been supported with a simulation using CST microwave studio software.     

基于双层金属光栅的中波红外多通道滤光片结构

提出一种多通道平面窄带滤光片阵列结构,该结构由双层金属光栅及其两侧的分布式布拉格反射器（DBRs）组成。所设计的多通道滤光片中心波长范围超过200 nm,每一个通道的中心波长可以通过调节光栅狭缝宽度来调节,从而实现多通道窄带滤光阵列。该结果为中波红外多通道窄带滤光片的设计提供了一条新的路径。     

基于非线性放大环镜和Lyot滤波器的多波长与耗散孤子锁模态开关型掺铥光纤激光器

报道了一种基于非线性放大环镜和Lyot滤波器技术的态开关型掺铥光纤激光器.通过仔细调节偏振控制器和泵浦功率,掺铥光纤激光器可以分别在多波长态和耗散孤子锁模态运行,并且两种态之间可以相互切换.对于多波长态,在光谱半功率值范围内能生成8个稳定的波长;对于耗散孤子锁模态,在1996 nm的中心波长处产生脉冲能量高达41.49 nJ,脉冲持续时间为2.4 ns,光谱带宽为29 nm的耗散孤子.不同运行态间的切换归因于偏振控制器导致的非线性放大环镜的功能的改变.     

长纤维高速过滤器性能优势分析

通过对净水厂沉淀出水和长江源水的过滤试验并与传统砂滤池及已在实际过程中推广应用的二类纤维过滤器进行了对比分析表明,本组研制的长纤维高速过滤器具有结构和性能上的明显优势。     

基于仿酉矩阵的紧支撑二元正交小波滤波器组的构造

高维小波是处理多维信号的有力工具,张量积和栅格结构的小波有其自身的特点,但在实际应用中,我们仍需要构造小波滤波器来满足特定情形下的需要以提高滤波的效果,而构造正交滤波器,在多相域里就等价于构造仿酉阵,在本文中,我们通过对仿酉矩阵的研究,证明二元一次对称的仿酉阵一定能够块对角化,利用这种性质,给出了不可分离的二元正交小波滤波器组及线性相位小波滤波器的构造,并给出了相应的例子．     

Synthesis, Crystal Structure and Photoluminescent Property of a Novel Silver(Ⅰ) Compound {[Ag(bpp)]2(Hphth)(NO3)·(H2O)2}n

Self-assembly of Ag(Ⅰ) nitrate, 1,3-bis(4-pyridyl)propane (bpp) and phthalic acid monopotassium salt (KHphth) in CH3OH-H2O solution produced the title complex,{[Ag(bpp)]2(Hphth)(NO3)·(H2O)2}n, which was characterized by single-crystal X-ray diffraction,elemental analysis, IR spectrum, and photoluminescent spectrum. Single-crystal X-ray analysis revealed that the complex crystallizes in a monoclinic system, space group P21/c, with α =15.4174(5), b = 8.6398(2), c = 25.2466(8) (A), β = 91.072(1)°, V = 3362.34(17) (A)3, Z = 4,C34H37N5O9Ag2, Mr = 875.43, Dc = 1.729 g/cm3, μ = 1.228 mm-1, F(000) = 1768, the final R =0.0749 and wR = 0.1580 for 5754 reflections with I ＞ 2σ(I). The Ag atom is coordinated by two N atoms from two bpp molecules in an approximately linear geometry. The Ag(Ⅰ) ions are linked by the bpp molecules to form one-dimensional zigzag chains propagating along the c axis. The Hphth-and nitrate counter-ions are bridged by solvent water molecules through hydrogen bonds to generate a one-dimensional chain extending along the b axis. Electrostatic interactions between cations and anions, extensive hydrogen bonds and π-π interactions are responsible for the three-dimensional supramolecular structure. In the solid state, the compound exhibits blue photoluminescence with the maximum at 436 nm upon excitation at 344 nm.     

微机械IMU数据建模与滤波方法研究

针对轮式移动机器人内部的微机械（MEMS）IMU进行研究，采用时间序列分析方法建立其随机噪声的ARMA模型，进而通过Kalman滤波有效地降低MEMSIMU随机噪声对其精度的影响，频域分析结果表明文中建模和滤波方法对提高MEMSIMU精度的有效性。     

Comparative Evaluation of Juices from Red-Fleshed Apples after Production with Different Dejuicing Systems and Subsequent Storage

In this work, two vintages (2019 and 2020) of red-fleshed ‘Weirouge’ apples were processed with the innovative spiral filter press technology to investigate juice production in an oxygen-reduced atmosphere. After pressing, a more brilliant red color and appreciably higher amounts of oxidation-sensitive constituents (ascorbic acid, anthocyanins, and colorless (poly)phenols) were seen in spiral filter pressed juices compared to those produced with conventional systems (horizontal filter press and decanter). In a subsequent stability study (24 weeks storage at 4, 20, and 37 °C), the color and phenolic compounds were monitored and differences in the juices produced with the different pressing-systems were widely maintained during the storage period. The analyses of the anthocyanins and colorless (poly)phenols were conducted by UHPLC-DAD-ESI-QTOF-HR-MS/MS and UHPLC-DAD. The spiral filter press emerged as a promising technology for the production of juices with a more attractive color and a better retention of oxidation-sensitive constituents during processing and storage compared to conventional juices.     

铁电液晶缺陷光子晶体调谐滤波器的设计

将铁电液晶作为缺陷层引入一维光子晶体中,用电场改变液晶分子的取向,形成光子晶体快速可调谐滤波器.用传输矩阵法研究了铁电液晶缺陷光子晶体的可调谐滤波特性,计算了电压和液晶材料参量对滤波器透射谱的影响.结果表明:改变电压能容易改变光子晶体滤波器透射峰的位置、强度、个数和带宽,实现良好的调谐滤波功能.     

红外图像的各向异性分段高斯滤波

提出了一种各向异性分段高斯滤波,这种方法除了考虑图像的尺度和方向特性外,还根据边缘区域可分特性,使用了分段滤波的方法来进一步解决边缘保持的问题.该方法通过本文所提出的一种图像噪音方差估计模型来确定图像的基准尺度,并由Hermite变换得到其方向角,然后再通过确定高斯模型的轴向比和自适应尺度,使对选择区域的滤波转变为对分段高斯模型的滤波,从而使计算的可靠性得到增强.从仿真结果可以看出,各向异性分段高斯滤波器在噪音去除和边缘保持的综合性能上要优于其他常用的滤波算法.