Broad-Band All-Optical Wavelength Conversion of Differential Phase-Shift Keyed Signal Using an SOA-Based Nonlinear Polarization Switch

Broad-band all-optical wavelength conversion of differential phase-shift keyed （DPSK） signal is experimentally demonstrated. This scheme is composed of a one-bit delay interferometer demodulation stage followed by a semiconductor optical amplifier （SOA） based nonlinear polarization switch. A wavelength converter for the 10 G b/s DPSK signal is presented, which has a wide wavelength range of more than 30 nm. The converted signals experience small power penalties less than 1.4 dB compared with the original signal, at a bit error rate of 10-9. Additionally, the optical spectra, the measured waveforms and the open eye diagrams of the converted signals show a high quality wavelength conversion performance.

Broad-Band FMR Linewidth of Co_2MnSi Thin Films with Low Damping Factor:The Role of Two-Magnon Scattering

The low Gilbert damping factor, which is usually measured by ferromagnetic resonance, is crucial in spintronic applications. Two-magnon scattering occurs when the orthogonMity of the ferromagnetic resonance mode and other degenerate spin wave modes was broken by magnetic anisotropy, voids, second phase, surface defects, etc., which is important in analysis of ferromagnetic resonance linewidth. Direct fitting to linewidth with Gilbert damping is advisable only when the measured linewidth is a linear function of measuring frequency in a broad band measurement. We observe the nonlinear ferromagnetic resonance linewidth of Co2MnSi thin films with respect to measuring frequency in broad band measurement. Experimental data could be well fitted with the model including two-magnon scattering with no fixed parameters. The fitting results show that two-magnon scattering results in the nonlinear linewidth behavior, and the Gilbert damping factor is much smaller than reported ones, indicating that our Co2MnSi films are more suitable for the applications of spin transfer torque.

Study of characteristics of long-period ground motion response spectra by using broad-band records of the Chinese Digital Seismograph Network

Broad band and very broad band (BB and VBB) records of Chinese Digital Seismograph Network (CDSN) from 65 earthquakes are used to calculate the horizontal relative displacement, relative velocity and absolute acceleration response spectra with critical damping ratio ζ =0.005, 0.01, 0.02, 0.05 and 0.10, respectively. The results show that it is insufficient to obtain the credible characteristics of long-period ground motion response spectra only with the common ground acceleration records in engineering, while the broad band records of CDSN, as an important supplementary to ground acceleration records, can be used to study the characteristics of long-period ground motion response spectra.

A tunable dual-broad-band branch-line coupler utilizing composite right/left-handed transmission lines

A tunable dual-broad-band branch-line coupler (BLC) utilizing composite right/left-handed (CRLH) transmission lines is presented. Two λ/4 segments consisting of CRLH transmission lines are added to each port to broaden the dual bands of the branch-line coupler. Numerical simulation and optimal design of the novel coupler are presented. The dual bands of the novel coupler are tunable and broad. The 1-dB bandwidth of each pass band is more than 16% of the central frequency.

网络基础设施建设对包容性绿色增长的影响——基于“宽带中国”战略的准自然实验

推动包容性绿色增长是解决我国低碳发展目标与经济增长矛盾的重要途径。本文基于2010~2022年我国地级市层面数据,利用熵权TOPSIS法从多个维度测算了289个地级市的包容性绿色增长水平,采用多期双重差分模型探究网络基础设施建设对包容性绿色增长的影响及传导机制。研究结果表明:(1)网络基础设施建设能够有效促进包容性绿色增长水平的提升;(2)网络基础设施建设对于非资源型城市包容性绿色增长效应显著高于资源型城市;(3)网络基础设施建设能够通过提高制造业集聚水平、促进产业结构升级、鼓励技术创新进一步提升包容性绿色增长水平。本文在进一步完善包容性绿色增长的现有分析框架基础上,为政府推进“宽带中国”战略实施、缩小区域发展差距以及促进经济高质量发展提供政策启示。

一种双简支―悬臂梁反共振隔振器设计分析与试验

[目的]为探究三元件型反共振隔振器的实现形式,提出一种由一根悬臂端含质量块的双简支-悬臂梁与一根双支撑梁所组成的机械装置(BAVI)。[方法]首先,分析双简支-悬臂梁的动态特性,推导其阻抗方程;然后,根据驱动点阻抗函数综合其低阶模型是单惯容与单弹簧二元件的串联结构,并解析低阶模型的等效参数;最后,通过装置试件设计与试验,验证其反共振特性和理论方法有效性,并在此基础上分析装置刚度特性及不同阻尼形式的效果。[结果]结果表明,当跨度比共振隔振器结构,具有“高静低动”刚度特性;在双简支-悬臂梁上采取阻尼措施后,可实现隔振区传递率以最大速率衰减的同时抑制共振峰的效果。[结论]所提机械装置证明了三元件型反共振隔振器的可实现性,提供了一种简易可行的工程结构。

一种S波段雷达通信电子战多功能宽带DAM的设计

本文创新性地提出了一种S波段多功能宽带DAM,首先介绍了该型DAM的顶层架构设计,接着介绍了各个功能组成模块的设计过程,最后给出了该型DAM的指标实现情况。该型DAM可以分时实现雷达、通信及电子战功能,最大瞬时带宽可达200MHz,支持任意波形产生,在多功能综合射频系统中具有良好的应用前景。

一种宽带宽波束圆极化微带天线的设计

本文设计了一款宽带宽波束圆极化微带天线。天线采用堆叠的双层圆贴片结构,结合四点顺序旋转馈电方式,实现了宽带圆极化辐射性能;在叠层圆贴片周边加载垂直接地金属柱环形阵,利用波束引向作用和等效零模谐振特性,在大带宽范围内实现了半功率波束宽度(HPBW)的有效展宽,并保证宽带宽波束内的圆极化辐射性能。对天线进行了加工、测试。实测结果表明,S 11小于-10 dB的阻抗带宽(4.54 GHz~11.50 GHz)为87%,覆盖了期望的应用工作频带6 GHz~10 GHz;轴比小于3 dB的带宽达到了33.1%(6.71 GHz~9.36 GHz);HPBW在6 GHz~8 GHz范围内接近100°,在整个带宽内均超过75°;除了9.5 GHz以上频段,工作频带内的6 dB轴比波束宽度覆盖范围都接近200°,表明天线在宽带和宽波束内具有良好的圆极化性能。

基于尖脉冲子波的高分辨率气枪震源设计

高分辨率气枪震源的设计是海上油气资源勘探的关键环节之一。分析震源子波形态与分辨率的关系,确定以尖脉冲子波作为震源优化的依据。基于非理想气体条件气枪子波模型对不同容量气枪的子波进行模拟,定量分析了不同容量气枪的主脉冲峰值及达到峰值的时间。提出通过调整阵列中不同容量气枪延迟激发时间和沉放深度,使阵列中各气枪主脉冲峰值同相叠加以构建尖脉冲子波的方法。在常规阵列的基础上设计了两种尖脉冲气枪阵列,并与常规阵列进行子波和频谱对比,结果表明:水深为20 m的条件下,基于尖脉冲子波设计的阵列较常规阵列虚反射效应和陷波点效应的压制效果更好;主峰值、峰-峰值和初泡比分别增大11.6%,12.4%,16.4%;兼顾了高频和低频,有效频宽增大14.5%;能谱展布范围更广,能量下传能力更强,提高了信噪比和分辨率。

基于人工表面等离子激元的宽带谐振天线

针对传统微带和介质谐振天线(DRA)带宽较窄和尺寸较大的问题,提出了一种基于人工表面等离子激元波导谐振腔的宽带天线。该天线人工表面等离子激元(SSPPs)波导由对称的H型单元结构组成,谐振腔由同轴探针馈电,利用波导单元偶模和奇模两种模式的色散特性,实现了天线带宽的显著增大。该天线工作频段为8.8~12.4 GHz,相对带宽为33.9%。在工作频带内,天线的辐射效率大于92%,最大增益达到了6.8 dBi。此外,天线为低剖面结构,整体尺寸较小,结构简单,利于各种无线通信和传感系统的集成。

Plasmon-enhanced broad-band quantum-cutting of NaBaPO4:Eu^2+,Er^3+phosphors with silver nano-particles

NaBaPO4:Eu^2+,Er^3+phosphors and Ag nano-particles(NPs)were prepared by the solid-state reaction and chemical reduction method,respectively.The fluorescence spectra and decay curves demonstrate the effective energy transfer from Eu^2+to Er^3+and the existence of three-photon quantum-cutting through two-step cross-relaxation of Er^3+.The quantum-cutting emission is peaked at 1534 nm with a broad excitation band centered at 352 nm,Plasmon-enhanced quantum-cutting of NaBaPO4:Eu^2+,Er^3+phosphors was realized by decorating Ag NPs.The largest enhancement factor is 1.395.It is hopeful to improve the photovoltaic conversion efficiency of Ge solar cells by using this phosphor.

基于改进T-B法的宽带高斯过程疲劳损伤分析

针对宽带高斯随机应力过程造成的疲劳损伤问题,本文提出一种基于改进Tovo-Benasciutti(T-B)法的疲劳损伤频域分析方法。通过不同参数形式的功率谱进行时域的疲劳损伤分析,针对T-B法中的关键参数bTB提出一个新的非线性函数模型。与原T-B法相比,新提出的函数模型bMTB可以考虑S-N曲线斜率参数m的影响,并以此为基础提出基于改进T-B法的疲劳损伤分析方法。以时域的雨流计数法结果作为基准,分别采用参数化功率谱和真实响应谱进行数值试验,并与现有的多种宽带高斯疲劳损伤分析方法进行对比,验证本文所提出的改进T-B法的准确性和适用性。

Implementation of the Broad-band User Access Network and the Study of the Key Algorithm for Improving the Performance of Asymmetrical Networks

This thesis is based on the design and development of ADSL access networks. We have completed the hardware and software functions in two main ADSL equipments: ATU C and ATU R. With the system design, we carry out researches to find out effective methods to improved performance in the following aspects: (a) how to allocate limited bandwith among services with different QoS requirements and (b) what is the effect of asymmetric links on TCP end to end flow control mechanism. We make detailed analyses and propose useful solutions to those problems we find. The main contents of this thesis are as follows: (1) the design and realization of ADSL access system. This part includes the principles of ADSL access technology, ADSL broadband access network architecture, and ATM over ADSL protocol models that we use in our system. We give detailed hardware and software design steps in this part, and list system testing results to show the system performance. In our hardware, the CPU is a RISC microprocessor. Combined with a high speed digital signal processor, the whole system can hold high reliability. Our software design platform is a pSOS multi task real time operation system. We have developed a series of hardware drivers besides other tasks for high level control and interruption processing. Currently, our system has reached the expected performance under test environment. Our next step is the development of DSLAM and in this part we give a feasible design scheme. (2) Packet scheduling policy in ADSL system. In order to optimize ATU R performance, we need a scheduling policy to regulate the order and number of packet output to the uplink. For this purpose, we study the scheduling algorithm design methods in a single network node and their performance. After studying the existing algorithms carefully, we first conclude certain important design principles and criterions for scheduling policy evaluation. And then by using service curve function, we make detailed performance analysis of a typical scheduling policy — the earliest deadline first. The advantage of characterizing service by using a function is that the service curve can provide a wide spectrum of service characterization. With this method, we first develop a generalized algorithm for calculating the deadlines used in the service curve based on the earliest deadline first policy, and then design a simplified computing program for an important curve. After that, holding fair bandwidth allocation and packet deadline guarantee as policy evaluation standards, we analyze this scheduling policy performance and propose solutions to those problems that we find. Finally, we, in theory, prove these improving algorithms. All these solutions and algorithms we design in this part are now under development in real systems and will enhance system performance. (3) Effects of asymmetric links on TCP performance and solutions. TCP is a widely used transmission control protocol. It regulates its forward data sending through reverse ACKs. What are the new problems to its flow control mechanism on asymmetric links and how to solve them are the two main points of this part. We first study the relationship between normalized bandwidth ratio, link buffer capacity and TCP link throughput under asymmetric link models. We find that TCP ack transportation on slow backward link is a key reason that causes the problems in TCP asymmetric links. Serving this as a start point, we present several improving solutions to TCP flow control algorithm and test them through simulation. Besides, TCP has been widely implemented in many networks. To give compatibility with current TCP end users, we use scheduling solutions to regulate data packet and ack packet transmission ratio onto uplinks. In the theoretical analysis of several typical scheduling policies, we find a feasible algorithm to control TCP data efficiency on asymmetric links. Finally, we prove those analyses and propose algorithm through simulation.

光谱干涉及其在非透明样品厚度测量中的应用

针对金属带材等非透明样品厚度的高精度原位测量问题,本文基于光谱干涉绝对距离测量的基本原理,提出了一种结构紧凑、全光纤的非透明样品厚度非接触式差分测量方法.首先介绍了光谱干涉的基本原理及绝对距离测量的具体实现,然后设计、搭建了一套全光纤差分光谱干涉测量非透明样品厚度的原理验证光路,并开展了原理验证实验,实现了标准量块厚度的高精度测量,最后对该方法的测量误差进行了分析,分析结果表明,采用该方法可以达到亚微米级的厚度测量精度.

宽谱强脉冲光(BBL)联合盐酸米诺环素和含青刺果油屏障修复霜治疗玫瑰痤疮

目的:评价综合疗法(联合盐酸米诺环素、宽谱强脉冲光和含青刺果油屏障修复霜)治疗玫瑰痤疮的临床有效性和安全性。方法:回顾性分析2021年1月-2021年6月就诊于上海交通大学医学院附属第九人民医院皮肤科门诊,主要表现为红斑、丘疹和毛细血管扩张的玫瑰痤疮患者20例。给予患者口服盐酸米诺环素50 mg,2次/日,连续4周;联合宽谱强脉冲光(Broad band light,BBL)治疗,1次/月,共3次;同时给予患者含青刺果油皮肤屏障修复剂进行日常护肤。治疗3个月后随访1个月,评估治疗有效性和安全性。结果:治疗后,患者治疗有效率为95%,持久性红斑、毛细血管扩张、丘疹和脓疱的治疗评均分较治疗前明显降低(P<0.05)。所有患者治疗期间均未出现严重不良反应。结论:针对以持久性红斑、毛细血管扩张、丘疹和脓疱为主要表现的玫瑰痤疮,盐酸米诺环素、BBL联合含青刺果油屏障修复霜的综合疗法安全有效。

基于宽带相位运动放大与机器视觉的结构振动频率识别

为了解决现有视觉技术难以准确测量结构微小振动的问题,该文提出了一种基于宽带相位运动放大(BPMM)和亚像素模板匹配算法的结构振动测量和频率识别方法。首先,利用相机拍摄结构的振动视频图像,并对图像中的噪声进行初步去除。其次,在不需要结构频率先验信息的情况下,在包含所有感兴趣频率的宽频带内进行滤波,选取合适的放大倍数进行微小振动视频的放大处理,再利用亚像素模板匹配算法从放大后的视频中提取结构的位移时程响应。最后,对提取的结构位移进行归一化处理,得到结构的实际位移时程响应,利用快速傅里叶变换(FFT)获取结构的振动频率。结果表明:BPMM算法既能实现结构微小振动位移幅值的放大,又能有效去除微小振动视频中的噪声,提高了图像的信噪比,从运动放大后的视频图像中可以准确地识别结构的振动频率。通过3层框架结构的室内试验和实桥试验对该文方法进行了验证,识别误差分别在1%和5%以内。该文方法可在不需要结构频率先验信息的情况下实现微小振动的盲放大处理,具有噪声鲁棒性好、计算量小及适用性强等优点,为结构微小振动测量提供了一种新思路,具有良好的应用前景。

X频段介质加载圆极化喇叭天线设计

设计了一款基于全介质极化器的X频段圆极化喇叭天线。该全介质极化器加载在线极化喇叭天线的前端,将线极化波转换为圆极化波,并有效辐射出去。同时,该全介质极化器还将天线的实测增益提高了约2 dB。天线的测试结果与仿真结果吻合较好。该天线在X频段(8~12 GHz)的实测S11均小于-10 dB,实测轴比在X频段内均小于3 dB,表明该圆极化喇叭天线具有宽带高增益特性。并且,该全介质极化器使用3D打印技术制作,具有加工简便、成本低的优点。该天线可应用于雷达、跟踪制导、卫星通信系统等领域。

宽波段光谱成像系统杂散光分析及抑制

宽波段光谱成像系统(0.4~1.7μm)在食品检测、农业生产、医学分析、刑事侦查等领域有广泛需求,光栅因其具有高色散本领和高环境稳定性的特点,成为宽波段光谱成像系统主流分光元件,但采用光栅分光的光谱成像系统存在多级次衍射光谱互相串扰问题,严重影响仪器的探测能力,为了得到准确的光谱信息,需对其进行有效的抑制。文中利用Tracepro光学分析软件对宽波段光谱成像系统的多级次衍射杂散光进行仿真分析,发展了利用分区域滤光片和线性渐变带通滤光片来抑制多级衍射杂散光的方法,并分析比较了它们对多级衍射杂散光的抑制效果。仿真分析结果表明:线性渐变带通滤光片能够有效地抑制多级次衍射带来的杂散光,光谱成像系统杂散光系数降低至10^(-4)量级,满足宽波段光谱成像系统对杂散光抑制要求。

基于结构复用的双频圆极化共口径天线设计

提出了一款低剖面宽波束高口径利用率的双频圆极化共口径天线。天线采用结构复用的设计理念,规划拓扑布局,设计不同类型的天线单元。上层采用微带环形贴片使其工作在无人机数据传输频段(1430~1444 MHz),下层采用微带圆形贴片使其工作在无人机遥控频段(2408~2440 MHz)。环形贴片既是低频辐射器,同时也作为高频引向器进行波束调控,实现宽波束特性。仿真和测试结果表明,该天线具有良好的阻抗匹配和圆极化特性,阻抗和轴比带宽均覆盖了无人机通信系统的两个工作频段,同时天线的剖面高度仅为0.07λ0。因此,实现了结构紧凑、性能可控的宽波束双频圆极化共口径天线,在无人机通信系统中具有潜在的应用价值。

防爆电驱车辆并联双驱动力变速系统研究

煤矿重型电驱防爆胶轮车传动系统一般采用低速电机搭配减速器的传动形式,由于车辆作业负载差异大、载重大、各种工况驱动速度差异大,因此,驱动系统装机功率大、效率低、能量损耗大。针对上述问题论文基于驱动电流闭环反馈控制策略,开发了一种煤矿重型电驱防爆胶轮车并联双驱动力混合驱动系统,并对并联双驱动力变速系统进行仿真测试和试验验证。结果表明:并联双驱动力变速系统全工况条件下相比于电机单驱系统综合能耗可降低约11.3%,考虑到并联双驱系统导致整车质量增加的影响,并联双驱动力变速系统全工况条件下相比于电机单驱系统综合能耗可降低约10%,其他条件不变整车续驶里程可提升10%,仿真与试验结论基本一致。