Thermostable Broad Band Polarizing PVA-Film: Theoretical and Experimental Investigations

In the present work, for the first time on the basis of poly(vinyl alcohol)(PVA), 2-(4-dimethylaminostyryl)-1-ethylquinolinium iodide(quinaldine red(QR)) and trisodium(4 E)-5-oxo-1-(4-sulfonatophenyl)-4-[(4-sulfonatophenyl)hydrazono]-3 pyrazolecarboxylate(tartrazine(T)), thermostable polarizing film in a wide range of spectra(λ_(max) = 394～511 nm) with polarization efficiency(PE) = 98% in absorption maximum and stretching degree(Rs) = 3.5 was developed. The basic spectral-polarization parameters(polarization efficiency and transmittance) of oriented colored PVA-films were measured and discussed. During the work it was found that oriented PVA-films are the phenomenon of anisotropy of thermal conductivity(λⅡ/λl). It is a very important parameter for the development of thermostable PVA-polarizing films. For the first time quantum-chemical calculations using density functional theory(DFT) approach for structural analysis and electronic spectrum of the QR were carried out via the B3 LYP/dgdzvp and TDB3 LYP/dgdzvp methods. Interpretation of absorption strips in visible region of spectrum was also reported. The excitation energies, electronic transitions and oscillator strengths for the studied structures have also been calculated(B3 LYP/dgdzvp). The NBO analysis and Mulliken atomic charges of the QR were carried out.

Broad Band Microstrip Patch Antenna Based on Foam-Filled and One Open Slot on Backward of Radiating Layer

A broadband microstrip patch antenna, loaded E-U-shaped open slot on backward of radiating layer is proposed and experimentally investigated. The antenna employs a foam-filled dielectric substrate, whose dielectric constant is within the lower end of the range. The proposed antenna has been designed for electromagnetic analysis including the impedance bandwidth, reflection coefficient, radiation pattern, and antenna gain. The open slot is loaded on the back radiated layer, which is perpendicular to the radiating edge of the oblong microstrip patch component, where the symmetric line feed is selected. This new technique used to increase the bandwidth and the gain of antenna through increasing current path by slot location, width and length on backward of radiating Layer. The main structure in this research was a single microstrip patch antenna planar with three layers operating at two resonant frequencies 4.440 GHz and 5.833 GHz. All the simulated results are confirmed by two packages of electromagnetism simulation. An impedance bandwidth (S11 ≤ ?10 dB) up to about 41.03% and 30.61% is achieved by individually optimizing its parameters. The antenna exhibits nearly stable radiation pattern with a maximum gains of 8.789 dBi and 9.966 dBi, which is suitable for Wi-Fi Band, satellite communications, and wireless presented. Whereas the results before this design that we have a proof of publication are 36.17% and 28.43%.

The characteristic of power flow in broad band dynamic vibration absorber

DVA (dynamic vibration absorber) is good for restrain of the resonance vibration in low frequency, especially under the condition that there are only one mode or two modes in a frequency band. It seems rather difficult to control the resonance vibration of elastic structures in high frequency, since usually there are so many modes in high frequency band. The broad band DVA is brought forward to reduce the resonance vibration of elastic structures. The broad band DVA is designed on the basis of the characteristic of power flow in structure in this paper. The broad band DVA is effective on absorbing the resonance vibration power flow of the most important modes. The ability of absorbing vibration for the broad band DVA is analyzed in detail. The results obtained in this paper provide a basis for the optimization design of the broad band DVA and the optimization positions on structures.

Higher degree moment tensor inversion of Mani earthquake using far-field broadband recording

Breakthrough point source model, extended earthquake source model is used to calculate more seismic source parameters in this paper. We express seismic source using higher degree moment tensors, to reduce a Iarge number terms originally presenting in higher degree moment tensor representation, Haskell rupture model is used. We in verted the source parameters of Mani earthquake in Tibet using broad-band body wave of 32 stations of Global Seismograph Network (GSN), the results show that it is a strike-slip fault, rupture direction is 75°, rupture duration is 19 s, the fault plan is φ=77°， δ5=88°, A=0°, the auxiliare plane is φ=347°, δ=90°, k=178°, and the fault dimension is 47 km×28 km. These results will give new quantitative data for earth dynamics and have practical meaning for seismic source tomography research.

Study on guided-mode resonance characteristic of multilayer dielectric grating with broadband and wide using-angle

Guided-mode resonance in a diffraction band of multilayer dielectric gratings may lead to a catastrophic result in laser system,especially in the ultrashort pulse laser system,so the inhibition of guided-mode resonance is very important.In this paper the characteristics of guided-mode resonance in multilayer dielectric grating are studied with the aim of better understanding the physical process of guided-mode resonance and designing a broadband multilayer dielectric grating with no guided-mode resonance.By employing waveguide theory,all guided-wave modes appearing in multilayer dielectric grating are found,and the incident conditions,separately,corresponding to each guided-wave mode are also obtained.The electric field enhancement in multilayer dielectric grating is shown obviously.Furthermore,from the detailed analyses on the guided-mode resonance conditions,it is found that the reduction of the grating period would effectively avoid the appearing of guided-mode resonance.And the expressions for calculating maximum periods,which ensure that no guided-mode resonance occurs in the requiring broad angle or wavelength range,are first reported.The above results calculated by waveguide theory and Fourier mode method are compared with each other,and they are coincident completely.Moreover,the method that relies on waveguide theory is more helpful for understanding the guided-mode resonance excited process and analyzing how each parameter affects the characteristic of guided-mode resonance.Therefore,the effects of multilayer dielectric grating parameters,such as period,fill factor,thickness of grating layer,et al.,on the guided-mode resonance characteristic are discussed in detail based on waveguide theory,and some meaningful results are obtained.

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

ｎｔｒｏｄｕｃｔｉｏｎＴｈｅｓｔｕｄｙａｃｈｉｅｖｅｍｅｎｔｓｏｎｃｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆｒｅｓｐｏｎｓｅｓｐｅｃｔｒｕｍｆｒｏｍｓｔｒｏｎｇｇｒｏｕｎｄｍｏｔｉｏｎｒｅｃｏｒｄｓｈａｖｅｂｅｎｗｉｄｅｌｙａｐｐｌｉｅｄｔｏｓｅｉｓｍｉｃｄ...

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.

A Broadband T/R Front-End of Millimeter Wave Holographic Imaging

A broadband T/R frond-end of active holographic imaging system is presented. Compact autodyne mode circuit structure front-end is adopted to achieve higher signal to noise ratio and higher reliability, which is beneficial to the after-end imagining. The factors that influence the dynamic range and the transverse resolution ratio of holographic imaging system have been analyzed. Wide-band oscillator, wide-band low noise amplifier and the tapered slot antennas are implemented to meet the requirements of the holographic imagining system. According to the measured results, the output power is uniform in the broadband working frequency. The sub-harmonic suppression is better than 25 dBc from the frequency of 28 GHz to 33 GHz. The isolation between antennas channel is greater than 20 dB. The experimental result shows that the performance of the front-end is good enough to meet the needs of active millimeter-wave holographic imaging system.

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。

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。

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。

Effect of Band Width on Fatigue Life under Random Stress Response

A fatigue life estimation method for offshore structures under random stress response is studied in this paper. The method of broad band cumulative frequency number is used to determine the effect of band width of stress frequency spectra on fatigue. A formula of correction factor for fatigue under broad band stress spectra is suggested and compared with that given by P. H. Wirsching.

Analysis of restriction factors of widening diffraction bandwidth of multilayer dielectric grating

In order to design a multilayer dielectric grating with wide-bandwidth diffraction spectrum, the restriction factors of both the reflection bandwidth of multilayer dielectric high-reflectivity mirror and the guided-mode resonance phenomenon are studied in detail. The reflection characteristics of high-reflectivity mirror in zeroth and 1st transmitted diffraction orders are quantitatively evaluated. It is found that the reflection bandwidth of high-reflectivity mirror in 1st transmitted diffraction order, which determines the final diffraction bandwidth of multilayer dielectric grating, is evidently compressed. Furthermore, it is demonstrated that the reducing of grating period is an effective approach to the elimination of guided mode resonance over a required broad band range both spectrally and angularly. In addition, the expressions for calculating the maximum period ensuring no guided mode resonance in the required bandwidth are derived. Finally, two high-efficiency pulse-compression gratings with broad-band are presented.

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。