信号解调的正交滤波器方法

信号的解调分析是通讯领域和机械故障诊断的常用方法。本文从数字滤波器的角度出发,提出了实现信号解调的正交滤波器法,即基于 Ｆ Ｉ Ｒ 正交滤波器方法和基于正交小波函数的正交滤波器方法。正交滤波器方法将带通滤波和希尔伯特变换的过程和功能有合二为一,实现过程方便。针对 Ｆ Ｉ Ｒ 正交滤波器方法的缺点,本文根据函数逼近理论,在理论上,证明了正交小波函数可以最佳一致逼近理想滤波器。并在具体应用上,介绍了采用正交小波函数构造正交滤波器时,参数的选择和信号解调分析的具体实施方法。采用正交小波函数设计的正交滤波器方法,带宽选择方便,相位的线性度高,正交性好,而且滤波器的滤波性能更优。可根据要求很方便地实现多通带信号滤波和多通带信号的解调分析     

正交莫尔(干涉)条纹区段跟踪计数细分法

提出一种正交莫尔(干涉)条纹信号的区段跟踪计数细分方法．根据正交信号的极性和幅值大小．将一个信号周期分成相等的8段．当信号采样点跨越相邻的两个区段时进行大数计数,实现一个信号周期的8细分;对不足1／8周期的条纹位移,根据测量起始点和终止点所在的区段和幅值大小进行二次细分,实现所需要的细分倍数．同时,由于区段的一致性,信号细分计算局限在相邻的两个区段内,避免了对多个区段进行组合,使二次细分计算更高效,更易实现高频响．文中给出了计数细分原理和实验结果．     

二次雷达S模式询问信号的解调译码实现

二次雷达信号的解调译码是空中交通管制系统实现正常通信的主要任务之一.在与传统的载波恢复实现解调的方法比较下,为了更加准确有效地实现二次雷达信号的解调译码,提出了一种根据信号脉内特征信息实现信号解调的方法.该方法将经过ASK、DPSK等方式调制的二次雷达S模式询问信号进行正交解调,获得信号包络与瞬时相位信息,实现信号恢复.通过实验验证,使用该方法能正确解译S模式询问信号.     

多谐差相信号激励下的频域建模

本文介绍一种新的激励信号—多谐差相信号（SPHS）来进行系统频域建模的方法．分析了多谐差相信号的产生和特点。以一个典型的单输人单输出系统为例．探讨采用多谐差相信号进行系统参数辨识的步骤，并且着重介绍了用MATLAB编程的具体实现，给出了参数辨识结果。     

基于H∞滤波器的多分量线性调频信号参数估计

针对多分量线性调频信号数据长度较短的情况，利用多分量线性调频信号的时空域信息，将其分解成多个单分量线性调频信号。针对未知噪声的情况，利用有限长H∞滤波器的良好瞬时特性和鲁棒特性，对每个单分量线性调频信号的参数进行估计，进而实现多分量线性调频信号参数估计。由于采用H∞平方根估计算法，此方法能够抑制递推计算的发散。计算机仿真表明了此方法的有效性。     

数字音频信号中的水印嵌入技术

随着数字技术的发展和计算机网络的普及，知识产权的保护越来越引起重视。数字水印是一项用于知识产权保护的新兴技术。文章在概述数字水印技术的基础上，着重介绍音频数字水印的特点和在数字音频信号中嵌水印的实现方法。最后简要讨论了作者提出的基于正交频分复用（OFDM）的音频数字水印技术。     

基于dsPIC30F6010A的通用型油耗仪输出信号接口设计

针对油耗仪输出TTL信号或输出正交信号的不同情况,提出一种基于dsPIC30F6010A正交编码器接口的通用型油耗仪输出信号接口模块设计方案,给出了其具体的软硬件实现.实践结果证明,该模块可以方便、准确地采集两类油耗仪输出信号.     

非正交多脉冲调制信号的非相干MMSE多用户检测

本文介绍了在同步高斯信道中对NMM(非正交多脉冲调制)信号的非相干MMSE多用户接收机。我们首先建立伪线性调制系统，然后用检测线性调制信号的方法来检测NMM信号。文中介绍了GLRT(Generalized Likelihood Ratio Test)判决器，并对MMSE接收机的性能进行了分析，其分析方法与分析针对NMM信号的解相关接收机性能是类似的。     

基于小波变换的荧光检测信号的去噪研究

用荧光分析法对物质进行定量分析时,荧光信号的去噪影响测量灵敏度.本文基于小波变换的多分辨率分析,研究了应用小波变换进行荧光信号滤波的方法,通过正交小波对荧光信号的分解,把频率成分复杂的荧光信号分解到互不重叠的频带,根据需要删除某些频带的荧光信号,然后用小波重构算法对荧光信号进行重构,实现对荧光信号的提取.并且通过对二氧化硫荧光暗电流信号提取实验,验证了小波变换的优越性.     

一种紧支集双正交小波基的构造

基于对偶尺度函数及对偶小波，提出了一种构造紧支集双正交小波基的算法，并给出严密的证明和推导过程。应用该算法，结合函数优化方法，构造出一系列包括样条小波、接近正交的双正交小波及其它具有特殊性质的双正交小波。该构造算法丰富了小波理论，可以广泛应用于信号分析、图像处理等领域。     

A new educational normal an intersectionality-led exploration of education,learning technologies,and diversity during COVID-19

The COVID-19 pandemic exacerbated the learning technologies disparity in the U.S. K-12 education system, thus broadening an already existing and troublesome digital divide. Low-income and minority students and families were particularly disadvantaged in accessing hardware and software technologies to support teaching and learning. Moreover, the homicide of George Floyd fostered a new wave of inquiry about racism and inequality, questioning often enabled with and through technology and social media. To address these issues, this article explores how parents and teachers experienced the pandemic through intersectional and digital divide-driven lenses. Data were collected from eight parents of underserved children and nine U.S. K-12 teachers to better understand challenges and best practices related to learning technologies during the pandemic. Data collection also focused on conversations about social justice, exploring specific needs and strategies for addressing technology inclusion and diversity in educational environments. Results from the study suggest that COVID-19 was a source of increased digital divide in terms of community and social support rather than economic means. At the same time, staying at home facilitated family discussions about racism and intersectionality-related themes. Implications are suggested for improving school communities and contexts in dealing with pandemic and emergency learning.     

细胞冻融策略优化及设备研究进展

低温冷冻保存是细胞治疗、辅助生殖等生物医学应用的使能技术之一.冷冻和复苏过程中,胞内外冰晶的形成和生长会对细胞产生损伤;其中,升降温速率又与冰晶的形成、生长有密切关系.本文在阐述程序化慢速冷冻和玻璃化快速冷冻两种细胞冻存方式及冷冻损伤两因素假说的基础上,对细胞特性、细胞外环境和升降温策略三个影响细胞冻存效果的要素进行分...     

基于情感化设计的亲子玩具应用研究

目的亲子玩具是满足儿童情感诉求的产物。基于情感化设计理念围绕亲子间爱与陪伴进行亲子玩具设计,旨在创新玩具产品及对现有的优秀亲子玩具产品进行分析评价的同时,促进儿童的健康成长、增进父母与孩子的情感交流。方法对亲子玩具的现状进行分析,剖析儿童与家长对亲子玩具的心理需求,运用情感化设计理念重点研究亲子玩具的材料、形态、色彩与交互,从中归纳出设计原则提出设计思路对现有的优秀的亲子玩具产品进行案例分析与设计实践。结论从材料、形态、颜色、交互4方面分析评价亲子互动玩具情感化设计方法,深化亲子玩具的感性功能。通过儿童与玩具、家长与玩具、家长与儿童3方相互影响,满足孩子与父母情感需求,促进双方的交流与互动。有助于家庭的和谐与孩子的健康成长。     

Evaluation of Different Techniques of Active Thermography for Quantification of Artificial Defects in Fiber-Reinforced Composites Using Thermal and Phase Contrast Data Analysis

For assuring the safety and reliability of components and constructions in energy applications made of fiber-reinforced polymers (e.g., blades of wind turbines and tidal power plants, engine chassis, flexible oil and gas pipelines) innovative non-destructive testing methods are required. Within the European project VITCEA complementary methods (shearography, microwave, ultrasonics and thermography) have been further developed and validated. Together with partners from the industry, test specimens have been constructed and selected on-site containing different artificial and natural defect artefacts. As base materials, carbon and glass fibers in different orientations and layering embedded in different matrix materials (epoxy, polyamide) have been considered. In this contribution, the validation of flash and lock-in thermography to these testing problems is presented. Data analysis is based on thermal contrasts and phase evaluation techniques. Experimental data are compared to analytical and numerical models. Among others, the influence of two different types of artificial defects (flat bottom holes and delaminations) with varying diameters and depths and of two different materials (CFRP and GFRP) with unidirectional and quasi-isotropic fiber alignment is discussed.     

Methods for Controlling Structure and Photophysical Properties in Polyfluorene Solutions and Gels

Knowledge of the phase behavior of polyfluorene solutions and gels has expanded tremendously in recent years. The relationship between the structure formation and photophysics is known at the quantitative level. The factors which we understand control these relationships include virtually all important materials parameters such as solvent quality, side chain branching, side chain length, molecular weight, thermal history and myriad functionalizations. This review describes advances in controlling structure and photophysical properties in polyfluorene solutions and gels. It discusses the demarcation lines between solutions, gels, and macrophase separation in conjugated polymers and reviews essential solid state properties needed for understanding of solutions. It gives an insight into polyfluorene and polyfluorene beta phase in solutions and gels and describes all the structural levels in solvent matrices, ranging from intramolecular structures to the diverse aggregate classes and network structures and agglomerates of these units. It goes on to describe the kinetics and thermodynamics of these structures. It details the manifold molecular parameters used in their control and continues with the molecular confinement and touches on permanently cross‐linked networks. Particular focus is placed on the experimental results of archetypical polyfluorenes and solvent matrices and connection between structure and photonics. A connection is also made to the mean field type theories of hairy‐rod like polymers. This altogether allows generalizations and provides a guideline for materials scientists, synthetic chemists and device engineers as well, for this important class of semiconductor, luminescent polymers.     

弹药储运方舱战技指标论证

目的通过研究弹药储运方舱的战技指标,为下一步设计和生产提供依据。方法结合弹药技术特点、弹药保障环境、弹药包装标准等约束因素,运用多约束设计理论确立弹药储运方舱战术技术指标。结果从质量尺寸指标、防护指标和使用指标等方面对弹药储运方舱系列指标进行了论证,确立了3个大项11个小项的战技指标。结论初步建立了弹药储运方舱战技指标体系。     

Fluorescence excitation-emission matrix spectroscopy with regional integration analysis for characterizing composition and transformation of dissolved organic matter in landfill leachates

Dissolved organic matter (DOM) obtained from landfill leachates was separated into hydrophobic base, hydrophilic matter (HIM), hydrophobic acid (HOA), and hydrophobic neutral fractions. The composition and transformation of the DOM and its fractions were investigated. The results show that the DOM isolated from young, intermediate, and old landfill leachates were mainly composed of tyrosine-, tryptophan-, and humic- and fulvic-like substances, respectively. The primary fractions of the DOM in leachates were HOA and HIM. The HOA and HIM fractions from young leachates predominantly contained tryptophan- and tyrosine-like materials, respectively. The HOA fractions in intermediate and old leachates were mainly composed of humic- and fulvic-like materials, whereas the HIM fractions were dominated by tryptophan-like materials and humic- and fulvic-like substances. The hydrophobic organic fractions and humic- and fulvic-like substances increased with time, whereas the HIM and the tyrosine-like materials decreased during the landfill process, rendering biological processing of leachates ineffective.     

木托盘受力性能理论分析及有限元模拟

目的对木托盘静载堆码时的力学性能进行理论分析和有限元模拟。方法建立木托盘顶铺板和纵梁板的力学模型,通过理论计算获得选用松木和杨木LVL 2种不同材料时的最大应力和最大挠度;按国家标准建立木托盘有限元模型,进行网格划分、施加载荷和约束后,获得选用松木和杨木LVL 2种不同材料时的最大等效应力值和最大变形量,并与理论分析结果进行对比。结果理论分析和有限元分析结果规律一致,最大应力均出现在中间纵梁板上,最大变形均发生在顶铺板上,且数值差距较小,2种分析方法均合理可行。结论该研究为木托盘的性能分析提供了有效的方法。     

Reactivation of latent herpes viruses in cosmonauts during a soyuz taxi mission

The hypothesis tested by this project is that space flight increases the incidence and duration of herpes virus reactivation and shedding in saliva. Saliva, urine, and blood samples were collected from 3 crew members who participated in a 14-day Odessa Soyuz taxi mission. Saliva samples were collected before, during, and after the mission, and blood and urine were collected before and after the mission. The saliva and urine samples were analyzed using the polymerase chain reaction to detect the presence of 3 important herpes viruses. Epstein-Barr virus (EBV) and varicella-zoster virus (VZV) were tested in saliva, and cytomegalovirus (CMV) was measured in urine samples. Plasma antibodies levels to these viruses were determined by enzyme-linked immunosorbent assay before and after flight. EBV reactivated before, during, and after flight; CMV reactivated before and after flight; and VZV reactivated during and after flight. In other studies, greater frequencies of positive samples and greater numbers of copies of viral DNA have been found. No increases in titer of antibodies to these viruses were found, suggesting that an immune response may not be necessary for reactivation.